Kazakhstan, officially the Republic of Kazakhstan, is a Eurasian country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world as well as the world's largest landlocked country, it has a territory of 2,727,300 km² (greater than Western Europe). Kazakhstan has the 62nd largest population in the world, with a population density of less than 6 people per square kilometre (15 per sq. mi.). It is bordered by Russia, Kyrgyzstan, Turkmenistan, Uzbekistan and China. The country also borders on a significant part of the Caspian Sea. Vast in size, the land in Kazakhstan is very diverse in types of terrain: flatlands, steppes, taigas, rock-canyons, hills, deltas, mountains, snow-capped mountains, and deserts. The terrain extends west to east from the Caspian Sea to the Altay Mountains and north to south from the plains of Western Siberia to the oases and deserts of Central Asia. The Kazakh Steppe (plain), with an area of around 804,500 square kilometres (310,600 sq. mi), occupies one-third of the country and is the world's largest dry steppe region. The steppe is characterized by large areas of grasslands and sandy regions. Important rivers and lakes include: the Aral Sea, Ili River, Irtysh River, Ishim River, Ural River, Syrdariya, Charyn River and gorge, Lake Balkhash, and Lake Zaysan. The climate is continental, with warm summers and colder winters. Precipitation varies between arid and semi-arid conditions. The Charyn Canyon is 150–300 metres deep and 80 kilometres long, cutting through the red sandstone plateau and stretching along the Charyn River gorge in northern Tian Shan ("Heavenly Mountains", 200 km east of Almaty). The steep canyon slopes, columns and arches rise to heights of 150–300 m. The inaccessibility of the canyon provided a safe haven for a rare ash tree that survived the Ice Age and is now also grown in some other areas. Bigach crater is a Pliocene or Miocene asteroid impact crater, 8 kilometres (5 mi) in diameter and estimated at 5 ± 3 million years old.