The geography of Mexico is diverse, featuring mountains, deserts, and coastal regions. The Sierra Madre mountain ranges run along the east and west sides of the country, while the central plateau, known as the Altiplano, is a significant landform. The country also has several major rivers, including the Rio Grande, which forms part of the border with the United States. Mexico has a long coastline along the Pacific Ocean to the west and the Gulf of Mexico to the east. The climate varies from arid in the north to tropical in the south, supporting a wide range of ecosystems and biodiversity. Major cities like Mexico City are located in the central region, surrounded by mountains and valleys.