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Longest Bridge Over Water

The Lake Pontchartrain Causeway, or the Causeway consisting of parallel, 23.87-mile (38.42 km) long spans is the world's longest overwater highway bridge and one of the oldest prestressed concrete bridges built in U.S. The twin bridges are supported by more than 9,500 hollow-cylinder pilings approximately 55 inches in diameter; the largest piles ever driven at the time of the first span's construction in 1955. The original Causeway was a two-lane span, that opened in 1956 at a cost of $30.7 million. A parallel two-lane span, 1/100th of a mile (15 m) longer than the original, opened on May 10, 1969 at a cost of $26 million. The Causeway has always been a toll bridge.