Channel Tunnel is a 31-mile tunnel linking England to France. The "Chunnel" represents an engineering feat -- 23 miles of the tunnel is submersed 150 feet under the waters of the English Channel. Trains travel side-by-side at nearly 100 mph through 5-foot thick concrete tubes, and a third tube positioned between the train lines serves as the maintenance and emergency facility. The project was fully operational in 1994.
Standing at 1,250-feet tall, the Empire State Building stood as the world's tallest building until the completion of the World Trade Center. One engineering marvel of the Empire State Building is the construction time; it took one year and 45 days to construct and was completed in 1931. At the top of the tower, the view spans 200 miles in any direction.
Connecting Marin County and San Francisco, the Golden Gate Bridge spans more than a mile. Completed in 1937, the bridge took four years to complete. The two towers stand 746 feet high and connect more than 80,000 miles of cable; each wire is one yard in diameter. The bridge continues to marvel engineers by withstanding devastating earthquakes such as the 1989 Loma Pima quake. The Golden Gate Bridge underwent a $400 million retrofit to prevent damage from later earthquakes.
The Itaipu Dam is located on the border of Brazil and Paraguay and spans 5 miles along the Parana River. Completed in 1991, the Itaipu Dam consists of enough steel and concrete to construct 300 Eiffel Towers. During construction, engineers moved more than 50 million tons of earth in order to create a bypass of the Parana River. The main dam is 65 feet and the powerhouse covers more than a mile. The eight hydroelectric generators supply 28% of Brazil's electric energy and 72% of Paraguay's energy.
Completed in 1976, the CN Tower is the world's tallest freestanding structure. Located in Toronto, the CN Tower stands 1,815 feet tall. Constructed at a rate of 118 feet per day, the tower can withstand hurricane-force wind gusts up to 260 miles per hour. The observation deck allows visitors to view a quarter mile down through the glass floor.
The Netherlands North Sea Protection Works is a series of surge barriers, floodgates and dams protecting residents form storm waters. The project began in 1927 with the construction of a 19-mile dam and finished in 1986 with the Eastern Schelde Barrier. Residents of the Netherlands built the structure in attempts to avoid flooding in a nation which sits below sea level.
Spanning close to 50 miles, the Panama Canal took 10 years to construct. Ships passing through the Panama Canal enter one of three locks in which water levels are raised and lowered, allowing vessels to pass. Ships enter at Gatun Locks and travel across Gatun Lake, then proceed to Pedro Miguel Lock and travel across Miraflores Lake. Finally, ships enter Miraflores Lock and are then lowered to sea level.
