Which mountain range makes the northeastern border of Spain?

The mountain range that makes the northeastern border of Spain is the Pyrenees. This range forms a natural barrier between Spain and France, stretching approximately 491 kilometers (305 miles) from the Bay of Biscay in the west to the Mediterranean Sea in the east. The Pyrenees are known for their stunning landscapes, diverse ecosystems, and numerous outdoor activities such as hiking, skiing, and climbing. The range also houses several national parks and peaks, including Aneto, which is the highest point in the Pyrenees at 3,404 meters (11,168 feet). This mountain range plays a significant role in the geography and climate of the region, influencing weather patterns and the natural environment on both sides of the border.