Precisely, how long is the Great Wall? This has been a long-unanswered question, as many dynasties in Chinese history built, modified or extended the Great Wall. But now, the State Administration of Cultural Heritage has announced a definite number after a seven-year investigation.

Twenty-one thousand one hundred and ninety-six point one eight Kilometers (21,196.18 km), That is the precise length of the Great Wall, which was included as a World Heritage Site in 1987.

Twenty-one thousand one hundred and ninety-six point one eight Kilometers (21,196.18 km), That is the precise length of the Great Wall, which was included as a World Heritage Site in 1987.

Built over two thousand years ago, the Great Wall is one of the largest construction projects ever completed. It's a series of fortifications made of stone, brick, wood and other materials built across the historical northern borders to ward off invaders.

Although it is also called "Wan Li Chang Cheng", which means ten-thousand li long wall in Chinese, this is only a description for a very, very long wall.

To get the precise length of the man-made masterpiece, the State Administration of Cultural Heritage began surveying the wall in 2006. More than 2,000 technicians worked on the comprehensive survey using state-of-the-art technology, in 15 provinces, municipalities and autonomous regions. The project proved to be very difficult as the Great Wall zigzags and winds up and down mountain edges and valleys.

Twenty-one thousand one hundred and ninety-six point one eight Kilometers (21,196.18 km), That is the precise length of the Great Wall, which was included as a World Heritage Site in 1987.

Twenty-one thousand one hundred and ninety-six point one eight Kilometers (21,196.18 km), That is the precise length of the Great Wall, which was included as a World Heritage Site in 1987.