The mountain range that forms a natural barrier between France and Spain is the Pyrenees. This mountain range extends approximately 491 kilometers, running east to west and marking the natural border between the two countries. The Pyrenees are known for their stunning landscapes, diverse ecosystems, and unique flora and fauna. The region attracts outdoor enthusiasts for activities such as hiking, skiing, and mountaineering. Along the mountain range are various historical sites and picturesque villages, enhancing its cultural significance. The Pyrenees play a crucial role in the geography and climate of southwestern Europe, shaping both nations' environments.