1. The Empire State Building, New York City

History
Construction of the Empire State Building began in March of 1930 on the site of the old Waldorf-Astoria Hotel at 350 Fifth Avenue at 34th Street. It was completed 14 months later in May, 1931. Designed by the architectural firm of Shreve, Lamb, & Harmon Associates, the Empire State Building, at 102 stories, was the tallest building in the world until the completion of the first tower of the World Trade Center in Lower Manhattan in 1972.

Location
350 Fifth Avenue, between 33rd and 34th Streets, New York, NY 10001

Description

Architects: Shreve, Lamb & Harmon Associates.
Builders: Starrett Brothers & Eken, Inc.

Height: 1,472 feet (448 meters) to top of antennae. 1,250 feet (391 meters) to 102nd floor observatory. 1,050 feet (320 meters) to 86th floor observatory.
Volume: 37 million cubic feet.

Area of Site: 83,860 square feet.

Cost including land: $40,948,900. (451,173,508 in today's money)

Cost of building alone: $24,718,000 (272,342,000 in today's money)

Construction schedule:
Excavation: Begun January 22, 1930, before demolition of old Waldorf-Astoria Hotel completed.
Construction: Begun March 17, 1930. Framework rose at the rate of 4.5 stories per week.
Cornerstone: Laid by Alfred E. Smith, former governor of New York, September 17, 1930.

Masonry completed: November 13, 1930.

Official opening: May 1, 1931, by President Herbert Hoover, who pressed a button in Washington, D.C. to turn on the building's lights.

Total time: 7 million man hours, 1 year and 45 days work, including Sundays and holidays.

Work Force: 3,400 during peak periods.

Building Materials:
Exterior: Indiana limestone and granite, trimmed with aluminum and chrome-nickel steel from the 6th floor to the top.
Interior lobby: Ceiling high marble, imported from France, Italy, Belgium and Germany.

2. The Itaipu Dam, Paraná River

The Itaipú hydroelectric power plant is the largest development of its kind in operation in the world. Built from 1975 to 1991, in a binational development on the Paraná River, Itaipú represents the efforts and accomplishments of two neighboring countries, Brazil and Paraguay. The power plant's 18 generating units add up to a total production capacity of 12,600 MW (megawatts) and a reliable output of 75 million MWh a year. Itaipú's energy production has broken several records over the recent years, after the last generating unit was commissioned in 1991. The generation of 77.212.396 MWh a year in 1995 will again be surpassed in 1996, and the new record will be around the 80 million MWh a year mark.

The magnitude of the project can also be demonstrated by the fact that in 1995 Itaipú alone responded for 25% of the energy supply in Brazil and 78% in Paraguay. The power plant is also a major tourism attraction in the Foz do Iguaçú area, having received around 9 million visitors from 162 countries. The Brazilian city of Foz do Iguaçu, also home of the famous Iguaçú Falls, is located at the Western tip of Paraná State, right by the border with Paraguay and Argentina.

General Outline of the Project

The Itaipú hydroelectric power plant, located 14 kilometers North of the International Bridge linking the cities of Foz do Iguaçú, Brazil, and Ciudad del Este, Paraguay, consists of a series of various types of dams a total distance of 7,744 meters with a crest elevation of 225 meters. The Powerhouse is located at the toe of the main Dam, most of it on the river bed and the rest on the Diversion Channel. The nominal power of the plant is 12,600 MW, divided between 18 generating units of 700 MW each, 15 of which are located in the main Powerhouse and the remaining three on the Diversion Channel. The Spillway is located on the right bank, and it has 14 segmented sluice-gates with a total discharge rate of 62,200 cubic meters per second (twice that of the highest flood- level on record). The Concrete Main Dam is of the hollow gravity type and is connected to the Spillway by a concrete buttress-type Wing Dam which continues thereon as a small Cardhfill dike. On the left bank a Rockfill Dam is linked to the Main Dam and at the other end to an Earthfill Dam. In order to build the main dam wall and the Powerhouse, the river was diverted through a Diversion Channel on the left bank.

The volumes of construction in Itaipú are also impressive. The volume of iron and steel utilized in the Dam structure would be enough to build 380 Eiffel Towers, and the volume of concrete used in Itaipú represents 15 times the volume utilized to build the Channel Tunnel between France and England. Itaipú is one of the Seven Wonders of the Modern World, according to a worldwide survey conducted by the American Society of civil Engineers (ASCE).To build the Itaipú Dam, workers reenacted a labor of Hercules: they shifted the course of the seventh biggest river in the world (Paraná River, at the Brazil/Paraguay border) and removed more than 50 million tons of earth and rock. The true marvel of Itaipú, though, is its powerhouse ... a single building that puts out 12,600 megawatts -- enough to power most of California".

3. The CN Tower, Toronto

It is fitting that television, the technological wonder that profoundly changed life in the 20th century, spurred the building of the era's tallest freestanding structure. In the late 1960's, Toronto's soaring skyline began to play havoc with signals from conventional transmission towers. Signals bouncing off the city's skyscrapers produced a number of problems, including the annoying phenomenon of "ghosting" on television sets. Weaker signals competed with stronger ones, giving viewers the effects of watching two programs at once. To improve the situation, Canadian National Railways, or CN, proposed building a transmission tower that would stand head and shoulders - and then some - above Toronto's tallest buildings.

A Toronto firm prepared the initial design, enlisting the aid of engineering experts the world over. Their original plan showed three towers linked by structural bridges. Gradually the design evolved into a single 1,815.5-foot-tall tower comprised of three hollow "legs." Foundation work began in 1973. Giant backhoes excavated more than 62,000 tons of earth and shale to a depth of 50 feet from a along the shore of Lake Ontario in Toronto harbour. Next, prestressed concrete and reinforced steel were arranged in a Y-shaped pattern 22 feet thick. Each hollow leg of the Y would carry its fair share of the tower's 130,000-ton burden.

The foundation took only four months to complete. The tower itself presented a challenge of height never before met by the technique of poured concrete. To meet that challenge, engineers designed a huge mold known as a slip form. Concrete was poured 24 hours a day, five days a week, and as it hardened, the mold moved upward by means of a ring of hydraulic jacks. The ascending slip form gradually decreased in girth to give the tower its tapering shape. When the tower reached the 1,100-foot mark, the builders made preparations for the SkyPod, a seven-story structure housing two observation decks, a revolving restaurant, a nightclub, and broadcasting equipment. The SkyPod is anchored by 12 steel-and-wooden brackets that were slowly pushed up the tower by 45 hydraulic jacks. Concrete formed the SkyPod's "walls," and a doughnut-shaped ring, called a radome, was added to its base to protect the delicate microwave dishes receiving radio and television transmissions. The SkyPod is reached by four high-speed, glass-fronted elevators whose rapid rise simulates a jetliner's takeoff, unless weather conditions call for a much slower ascent.

The concrete tower continues above the SkyPod, ending at the Space Deck 1,465 feet up. The Space Deck receives support from cantilevers extending out of the concrete section beneath it. After a 58-second elevator ride from the SkyPod below, visitors can enjoy breathtaking vistas from a glass-enclosed balcony. On a clear day they might be able to glimpse sites 75 miles away. For the last phase of construction, a Sikorsky Skycrane helicopter arrived to install the tower's 335-foot communications mast. One by one the helicopter lifted about 40 seven-ton sections of the mast to the top of the tower, where workers braved blustery March winds to receive them. When the sections were in place, they were secured by a total of 40,000 bolts. Afterward, the entire mast was covered by a fiberglass-reinforced sheathing to prevent icing.

Of interest to Torontonians since construction began, the CN tower gained additional fans with the arrival of the helicopter. Nicknamed Olga, its daily schedule was printed in newspapers, and changes were announced as breaking news on radio and television. With Olga, the mast assembly took a little longer than three weeks; without Olga, the job would have lasted six months. Completed in 1975, the tower had cost $57 million (236,216,000 in today's money) to build, a bargain compared with other modern wonders. It also boasted incredible statistics of precision and safety. During construction, surveyors' transits up to a thousand feet away focused on optical plumbs mounted on the slip-form base. The constant surveillance kept the structure an incredible 1.1 inches within plumb.

Engineers established a wind-tolerance standard for the tower of 260 miles an hour, a level well above nature's most extreme demands. Counterweights on the antenna correct for wobble in high winds. Because the tower is an easy target for lightning, copper grounding wires were installed. As a result, visitors can safely view some 75 spectacular strikes a year. The CN Tower is a work in progress. In recent years the tower gained two new elevators to accommodate an increase in visitors. To accomplish this, the 2,579-step metal staircase was moved to the interior of the structure. In addition, a glass floor was added to the SkyPod's observation deck. Brave visitors, the majority not surprisingly children, inch out over the visual void. More often than not the experience is pronounced, "Awesome!" Almost twice as tall as the Eiffel Tower and more than three times the height of the Washington Monument, the CN Tower has taken proud ownership of Toronto's skyline, while exorcising the ghosts from its TV sets.

4. The Panama Canal, Panama

Among the great peaceful endeavors of mankind that have contributed significantly to progress in the world, the construction of the Canal stands as an awe-inspiring achievement. The unparalled engineering triumph was made possible by an international work force under the leadership of American visionaries, who made the centuries-old dream of uniting the two great oceans a reality. In 1534, Charles I of Spain ordered the first survey of a proposed canal route through the Isthmus of Panama. More than three centuries passed before the first construction was started. The French labored 20 years, beginning in 1880, but disease and financial problems defeated them.

In 1903, Panama and the United States signed a treaty by which the United States undertook to construct an inter-oceanic ship canal across the Isthmus of Panama. The following year, the United States purchased from the French Canal Company its rights and properties for $40 million and began construction. The monumental project was completed in ten years at a cost of about $387 million (7,192,727,272 in today's money).. Since 1903 the United States has invested about $3 billion in the Canal enterprise, approximately two-thirds of which has been recovered. The building of the Panama Canal involved three main problems -- engineering, sanitation, and organization. Its successful completion was due principally to the engineering and administrative skills of such men as John F. Stevens and Col. George W. Goethals, and to the solution of extensive health problems by Col. William C. Gorgas. The engineering problems involved digging through the Continental Divide; constructing the largest earth dam ever built up to that time; designing and building the most massive canal locks ever envisioned; constructing the largest gates ever swung; and solving environmental problems of enormous proportions.

5. The Channel Tunnel, The English Channel

For centuries, the English Channel separating Great Britain from the rest of Europe has served as a near impregnable barrier to would-be invaders, protecting England’s sovereignty while keeping the nation culturally and socially distinct from its neighbors. The $15 billion Channel Tunnel (informally called the “Chunnel”), which began operations in 1994, provides the first land link between England and continental Europe. The Chunnel is 31 miles long; 23 miles of this distance is underwater. At present, it consists of three interconnected tubes; one rail tunnel in each direction and a service tube. For facts about the Chunnel, a diagrams, and information about traveling Europe by rail, see the Eurostar page. Obviously, the only way to experience the Chunnel is to take a train through it, so you’ll have to find some other activities to fill your time in two of the most culturally and historically rich nations in the world.

6. The North Sea Protection Works, Netherlands

For many, the image out of the Dutch fight against the North Sea rests in the figure of a young boy valiantly saving his town by using a finger to plug a hole in the dike. But this familiar hero is a fictional one, a creation of American author Mary Mapes Dodge in her book, Hans Brinker. In reality, heroism falls on all the Dutch, who for more than a millenium have been wresting precious agricultural lands from the sea and fighting to hold on to them. Their greatest achievement-a colossal fun in the dike-if the vast and one dress project known as that Netherlands North Sea protection works. Because much of the Netherlands lies below sea level, normal tides would daily inundate about half the country if previous generations of industrious Dutch had not raised dikes and dams. Severe storms often cause tidal waters to crash into the dikes and inundate rivers and estuaries. Although all of the coastal areas are threatened, two particularly vulnerable ones are the large tidal inlet formerly known as the Zuider Zee and the delta created by the Rhine and Meuse rivers in the southwestern corner of the country.

Dutch engineers purse propose that the Zuider Zee be dammed and drained in the 19th century, but the government was reluctant to tackle such an immense project. Then, in 1916, a furious storm hit the northern provinces. The difficulties of wartime agricultural production were compounded, and the way was paved for the damming of the Zuider Zee.The dam enclosing the Zuider Zee was built in two sections using traditional materials. Beginning in 1923, workers laid boulder clay in parallel layers and filled the space in between with sand, stones, and handmade, mattresses fashioned from brushwood. To curtail erosion, larger mattresses ballasted with chains and stones were sunk in the estuaries channels. Dredges, cranes, tugboats, and barges were engaged in the erection of the main dam, 300 feet wide at sea level and 25 feet high at the level of its causeway. As the tide turned on the final day of construction, fill tumbled into the dam's last gap, transforming the inlet into a freshwater lake, renamed the Ijsselmeer. The finished dam contains sluices for draining excess water and locks for maintaining shipping.

After the damming came the draining. In all, more than a half million acres of polders, or reclaimed farmland, emerged from the bottom of the former Zuider Zee. Young Dutch farmers clamoring for the right to settle the new polder lands, because farms on new, unobstructed land were far more suitable for modern, mechanized farming methods than traditional farms in older areas.In 1953, the "storm of the century" howled across the North Sea and into the Netherlands, testing the strength of the Zuider Zee enclosure. It held, with damage to the causeway heavy in places. The country's unprotected southwestern provinces felt the full brunt of the storm, with water surging over seawalls and up the delta's wide waterways. More than 1,800 people lost their lives, and livestock numbering in the hundreds of thousands perished. The country then realized that the long-intended plan to safeguard the southwestern delta, the Delta Plan or Delta Project, must be mobilized.

The plan would undergo a many incarnations. The last one involved a damming four estuaries in the middle of the delta while leaving open channels to Rotterdam in the north and Antwerp, Belgium, in the south. A two-mile-long surge barrier in the Oosterschelde estuaries was the most complex and sophisticated piece of the project.Originally, the Oosterschelde was to be a closed barrier. But lobbying by fishermen and conservationists resulted in the switch to a movable barrier. To facilitate construction, engineers fashioned islands on three sandbars in the estuaries and constructed work harbors, material yards, and work sites there. A dam connected two of the islands, effectively creating three channels in the estuaries, each to receive a section of the surge barrier.

The movable barrier consists of 65 concrete piers weighing 18,000 tons apiece. The piers support 300- to 500-ton steel gates and their hydraulic machinery, as well as a roadway above and load-bearing beams below. Constructed on the work islands, the piers and their mechanisms had to be lifted into precise positions in the estuary. But the type of equipment needed for such gargantuan and specialized tasks did not exist anywhere in the world; it had to be invented. The Oosterschelde barrier also honored traditional methods. As part of the measures taken to stabilize the sea floor, mattresses were laid under each pier to prevent erosion. They were not the hand-built weaving of trees and brush used to close the Zuider Zee, however. Instead, they were high-tech sandwiches of sand and gravel between space-age fabric covers. The Oosterschelde project finished in 1986. Since then, the Dutch have taken additional measures, including the completion in 1997 of the barrier that protects the port of Rotterdam. "In terms of magnitude," an American trade journal wrote, the North Sea project "approaches of the Great Wall of China. In terms of complexity and technical sophistication, it approaches the lunar shot. It is unique, expensive, and quite unlike any other civil engineering project to be found on this planet."

7. The Golden Gate Bridge, San Francisco

The Golden Gate Bridge links San Francisco with Marin County in absolute splendor. The bridge is one of the architectural marvels of the Twentieth Century and a testament to human strife, as it was constructed during the years of the Great Depression. For years, the Golden Gate Bridge held the title as the longest suspension bridge in the world. Before its completion in 1937, the bridge was considered impossible to build, due to persistently foggy weather, 60-mile-per-hour winds, and strong ocean currents, which whipped through a deep canyon below. In fact, the bridge is commonly known as the "Bridge that couldn't be built." Despite these unforgiving natural elements, the bridge was constructed in a little more than four years. The total cost was $35 million (447,227,000 in today's money). The total length of the bridge spans 1.2 miles. Eleven men lost their lives during the construction of the bridge.

Even today, the massive spans of the bridge are often shrouded in fog. The bridge sways 27 feet to withstand winds of up to 100 miles per hour. International Orange was the color chosen for the bridge because it blended well with the bridge's natural surroundings. The two great cables extending from the bridge contain 80,000 miles of steel wire, which is enough to circle the equator three times. The concrete poured to cement the bridge into the stormy waters below could have also been used to pave a five-foot wide sidewalk from New York to San Francisco. Because of the Golden Gate Bridge, San Francisco is one of the premier skyline cities in the nation. It was a triumphant day in the history of the city when the bridge was completed on May 27, 1937. Over 200,000 people celebrated the grand opening of the Golden Gate Bridge by walking its length. The following day, a dedication ceremony was held to officially christen what would become the architectural trademark of the city. The regular flow of vehicular traffic began the next day.

Efforts to begin the construction on the bridge began as early as 1928. The process would entail the efforts of six counties in Northern California. In 1928, the counties formed a Golden Gate Bridge and Highway District. In 1930, the voters appropriated a $35 million bond issue to finance the building of the bridge. For many years following, Joseph Baerman Strauss, a distinguished engineer, dreamed of raising a span across the Golden Gate. It was in response to his vision that people first started saying that the bridge could not be built. But, amazingly enough, Strauss held fast to his vision, and a span was eventually raised across the Golden Gate Bridge. The actual work on the bridge began on January 5, 1933. It was completed four-and-one-half years later. The result astounded the fiercest of Strauss's critics. To this day, the bridge is admired for its magnitude and beauty.

The bridge is nothing short of a powerful force meant to combat nature. The often mighty winds from the Pacific Ocean are sustained by a mid span swing of 27 feet. The two towers of the bridge rise an impressive 746 feet, which is 191 feet taller than the Washington Monument. The pier of the bridge is only 1,215 feet from the shore, the distance between the two towers that support the cables, which in turn, support the floor of the bridge is 4,200 feet. These two cables are the largest bridge cables ever made at a little over 361 feet in diameter.

Today, pedestrians and bicyclists are still allowed to cross the bridge on pathways with breathtaking views of the city, Alcatraz, and the Marin Headlands. The bridge toll for vehicles is $3 when entering San Francisco. The first exit of the Marin side of the bridge is Visa Point, which provides a magnificent view of the San Francisco skyline. But, the best way to view the bridge is to walk across. This usually takes about an hour.

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