China is a populous nation in East Asia whose vast landscape encompasses grassland, desert, mountains, lakes, rivers and more than 14,000km of coastline. Capital Beijing mixes modern architecture with historic sites such as the Forbidden City palace complex and Tiananmen Square. Shanghai is a skyscraper-studded global financial centre. The iconic Great Wall of China runs east-west across the country's north. China emerged as one of the world's earliest civilizations in the fertile basin of the Yellow River in the North China Plain. For millennia, China's political system was based on hereditary monarchies known as dynasties, beginning with the Xia dynasty (c. 2070 bce). China's climate is mainly dominated by dry seasons and wet monsoons, which lead to pronounced temperature differences between winter and summer. The climate in China differs from region to region because of the country's highly complex topography. China has become a major tourist destination following its reform and opening to the world in the late 1970s instigated by Deng Xiaoping. China's growing economy is also generating a surge in business travel.