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.
Seoul subway is the longest subway system in the world. Shanghai Metro, the second longest metro system in the world, has been operational since 1993. Image courtesy of Baycrest. Beijing Subway is the oldest metro system in China and the third longest in the world. Image courtesy of Hat600.