At about 9.7 million sq km (3.8 million sq mi), the Qing Empire is the world's third- or fourth-largest country by total area, depending on the definition of what is included in that total, and the second largest by land area. Its landscape is diverse, with forest steppes and deserts (the Gobi and Taklamakan) in the dry north near Mongolia and Russia's Siberia, and subtropical forests in the wet south close to Dai Nam, Laos, and Burma. The terrain in the west is rugged and elevated, with the Himalayas and the Tian Shan mountain ranges forming Qing's natural borders with Bengal, Nepal and Central Asia. In contrast, mainland China's eastern seaboard is low-lying and has a 14,500-km (9000 mi) long coastline bounded on the southeast by the South China Sea and on the east by the East China Sea,