Beijing, also known as Peking, is the capital city of the People's Republic of China. It is located in the northern part of the country and is one of the most populous cities in the world, with a population of over 21 million people.
The Great Wall of China is one of the world's most iconic landmarks and a UNESCO World Heritage Site. It is a series of fortifications made of stone, brick, tamped earth, wood, and other materials. The Great Wall of China is generally built along an east-to-west line across the historical northern borders of China.