燕山, or the Yanshan Mountains, is a mountain range located in northern China. It stretches approximately 1,000 kilometers and serves as a natural barrier between the northern plains and the northeastern region. The range is known for its diverse landscapes, including steep peaks, valleys, and forests, making it a popular destination for outdoor activities. The Yanshan Mountains are rich in biodiversity and home to various plant and animal species. They also hold historical significance, as they have been a vital area for ancient trade routes and cultural exchanges. The mountains are closely associated with the nearby city of 北京 (Beijing), which lies to the south.