The Great Wall can be found in China. This ancient fortification stretches over 13,000 miles and was built to protect against invasions from nomadic groups and other military incursions. Construction of the wall began in the 7th century BC, and it underwent several expansions and renovations over the centuries, especially during the Ming dynasty. The Great Wall features various materials, including earth, wood, bricks, and stone, depending on the region and time period of construction. Today, it stands as a UNESCO World Heritage site and is one of the most recognized symbols of China.