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.
The system was opened in 1896 making it the second oldest system in the world. OVER thirty of the world's metro systems offer either a complete network or partial system of automated (driverless) trains. The longest of these systems is the Dubai Metro in the United Arab Emirates at 74.6 kilometers.