Chongqing Municipality lies in the southwest of China; and area through which the upper reaches of the Yangtze River passes from west to east. Covering an area of 82.4 thousand square kilometers (about 204 million acres), it is the biggest municipality in China. The area features a geographic nature of mountains and rivers thus is a very popular destination during foreign visitors' China tour. The population is about 31.3 million, and the tens of ethnic people make up 5.7 % of the total. Under the sub-tropical monsoon climate, Chongqing features warm winters and hot summers. The yearly average temperature is 17.0 oC-18.8 oC (62.6oF-65.8oF), and it can be very hot in summer with the average temperature 27oC-29oC (80.6oF-84.2oF).