Just some facts about the World Trade Center or WTC or sometimes referred to as Twin Towers, located in Lower Manhattan, USA.

There are seven buildings in the complex, but the two most prominent are the two tallest towers called North Tower and South Tower where both having 110-story. World Trade Center Towers were the world’s tallest buildings from 1972 to 1973.

WTC were destroyed by two commercial air planes, Boeing 767, which was hijacked by al-Qaeda terrorist group. The terrorist plunged one air plane on each tower on the morning of 11th September 2001.

Although the towers are considered steel buildings, which was designed by Minoru Yamasaki in the early 1960s using a tube-frame structural design, both towers collapsed at the end believed to be cause by the intense heat which melted the steel structures.

The South Tower collapsed first after burning for almost 1 hour. The North tower collapsed about half hour later. The collapsed of the two towers caused 2,750 deaths and it took 8 months to cleanup the area.

Now, the place is being rebuilt and once completed there will be six new skyscrapers and a memorial. The rebuilding process of the complex started in 2002. The towers will be replaced with Freedom Tower and the whole rebuilding process is expected to be completed in the fourth quarter of 2013.