Pentagon vs Pisa Tower

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The Pentagon is the headquarters building of the United States Department of Defense.

As a symbol of the U.S. military, the phrase The Pentagon is also often used as a metonym for the Department of Defense and its leadership. Located in Arlington County, Virginia, across the Potomac River from Washington, D.C., the building was designed by American architect George Bergstrom and constructed by contractor John McShain. Ground was broken on 11 September 1941, and the building was dedicated on 15 January 1943. General Brehon Somervell supplied the important motivating power behind the project; Colonel Leslie Groves was responsible for overseeing the project for the U.S. Army. The Pentagon is the world's largest office building, with about 6,500,000 sq feet (600,000 m2) of space, of which 3,700,000 sq feet (340,000 m2) are used as offices. Some 23,000 military and civilian employees, and another 3,000 non-defense support employees, work in the Pentagon.



It has five sides, five floors above ground, two basement levels, and five ring corridors per floor with a total of 17.5 mi (28.2 km) of corridors. The fundamental five-acre (20,000 m2) pentagonal plaza is nicknamed'ground zero' on the presumption that it would be a prime target in a nuclear war.On 11 September 2001, exactly 60 years after the building's construction began, American Airlines Flight 77 was hijacked and flown into the western side of the building, killing 189 people (59 victims and the five terrorists on board the airliner, as well as 125 victims in the building), according to the 9/11 Commission Report. It was the first major foreign attack on Washington's governmental facilities since the town was burned by the British during the War of 1812. The Pentagon is listed on the National Register of Historic Places and is a National Historic Landmark.

Source: Wikipedia

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The Leaning Tower of Pisa (Italian: Torre pendente di Pisa) or simply the Tower of Pisa (Torre di Pisa [?torre di ?pi?za]) is the campanile, or freestanding bell tower, of the cathedral of this Italian city of Pisa, known globally for its almost four-degree lean, the result of an unstable foundation. The tower is situated behind the Pisa Cathedral and is the third-oldest structure in the city's Cathedral Square (Piazza del Duomo), following the palace and the Pisa Baptistry. The height of this tower is 55.86 metres (183.27 feet) from the ground on the low side and 56.67 metres (185.93 feet) on the high side. The width of the walls at the base is 2.44 m (8 feet 0.06 in). Its weight is estimated at 14,500 metric tons (16,000 short tons). The tower has 296 or 294 steps; the seventh floor has two fewer steps on the north-facing staircase. The tower began to lean during construction in the 12th century, due to soft ground which could not properly support the structure's weight, and it worsened through the completion of building in the 14th century. By 1990, the tilt had reached 5.5 degrees. The structure was stabilized by remedial work between 1993 and 2001, which decreased the tilt to 3.97 degrees.

Source: Wikipedia