Mertropolis



Mertropolis is an underwater city protected by an oxygen-containing dome featured in the The Adventures of Super Mario Bros. 3 episode, The Ugly Mermaid. Bowser planned to take over the city using his Doomsub, renaming it "Kooptropolis", but his plans were foiled by the Mario Bros, who used a group of Jelectros against his submarine.

The town's name comes from a portmanteau of the words "mermaid" (or possibly "merman") and "metropolis", a word for a big city.