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.
First opened in 1927 and greatly expanded in preparation for the 1963 Summer Olympics, Tokyoâs mass transit system, only part of which runs underground, is the busiest in the world, ferrying more than 8.7 million commuters a dayâand more than 3.2 billion annuallyâalong its 200 miles of tracks.