Mutianyu is a section of the Great Wall of China located in Huairou County 70km northeast of Beijing.

First built in the mid-6th century, it has the largest construction scale and best quality among all sections of Great Wall. Built mainly with granite, the wall is 7-8 meters high and the top is 4-5 meters wide. Comparing with other sections of Great Wall, Mutianyu section possesses some unique construction characteristics.
# Watchtowers and over-towering pass densely scatter along this section of Great Wall - exactly, 22 watchtowers in the 22500-meter-long wall.
# Both the outer and inner parapets are crenellated with merlons, so that shots could be fired at the enemy on both sides - a feature very rare on other parts of the Great Wall.
# The Mutianyu Pass consists of 3 watchtowers, one big in the center and two smaller on both sides. Standing on the same terrace, the three watchtowers are connected each other inside and compose a rarely seen structure among all sections of Great Wall. Besides, this section of Great Wall is surrounded by woodland and streams. The Forest-coverage Rate is over 90 percent