Construction Periods: The construction of the Great Wall started in the 7th century BC during the Warring States period (476–221 BC). Different dynasties, including the Qin, Han, and Ming, contributed to its construction and maintenance over the centuries.

Purpose: The primary purpose of the Great Wall was defense against invasions by nomadic tribes. It also served as a means of border control, allowing the imposition of duties on goods transported along the Silk Road.

Length and Sections: The Great Wall stretches over 13,000 miles (21,000 kilometers). There are various sections, with the most famous ones being near Beijing, including Badaling and Mutianyu.

Ming Dynasty Reconstruction: The majority of the existing wall is from the Ming Dynasty (1368–1644). During this time, the wall was extensively reconstructed and strengthened.

UNESCO World Heritage Site: The Great Wall has been recognized as a UNESCO World Heritage Site since 1987, acknowledging its cultural significance and historical importance.

Tourism: In contemporary times, the Great Wall has become a symbol of China and a major tourist attraction. Visitors can explore different sections, and some parts have been extensively restored to their former glory.

Conservation Challenges: Despite its cultural significance, the Great Wall faces challenges such as natural erosion, weathering, and, in some cases, human impact. Conservation efforts are ongoing to preserve this iconic structure.