The Great Wall of China (万里长城) is a series of fortifications that were built across the historical northern borders of ancient Chinese states and Imperial China as protection against various nomadic groups from the Eurasian Steppe. Several walls were built from as early as the 7th century BC, with selective stretches later joined by Qin Shi Huang (220–206 BC), the first emperor of China.

Apart from defense, other purposes of the Great Wall have included border controls, allowing the imposition of duties on goods transported along the Silk Road, regulation or encouragement of trade and the control of immigration and emigration. Furthermore, the defensive characteristics of the Great Wall were enhanced by the construction of watchtowers, troop barracks, garrison stations, signaling capabilities through the means of smoke or fire.

Mutianyu (慕田峪) is a section of the Great Wall of China located in Huairou District within the city limits of Beijing 70 kilometers northeast of the center of the city. As one of the best-preserved parts of the Great Wall, the Mutianyu section of the Great Wall used to serve as the northern barrier defending the capital and the imperial tombs.

Below is a selection of photos taken during a visit to the Mutianyu section of the Great Wall on May 29, 2010. Click on a small photo for a larger view, then select the next one with the cursor keys or the arrows on either side of the photo.