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.
One oft-cited candidate for the worldâs longest metro network is the one in Seoul, which only opened in 1974 but by 2013 included 987.5km of route on 18 lines. That's pretty much enough to get you from London to Marseille. No other city comes close.