1 The pancreas is an abdominal gland situated behind the stomach in the upper abdomen.  The main function of the pancreas is to secrete hormones and enzymes that help with digestion and regulate blood sugar (glucose) metabolism.
See also: List of tram and light rail transit systems. The Shanghai Metro is the longest metro system by route length. The Beijing Subway is the metro system with the highest ridership. The New York City Subway has the most stations.
Most experts rate Tokyo as the world's biggest city because of the size of the population in the larger urbanised area. Many of the 30 million people who are said to live in the city of Chongqing are actually agricultural workers living in a rural setting.