Percy, Annabeth, and Grover leave the truck and walk the streets of Las Vegas. They arrive at a dead end where a doorman at the Lotus Hotel and Casino kindly invites them in. Inside they are blown away by what they see: a huge lobby/game room with every kind of game and every kind of snack you can imagine.
Atlantis is the location of Poseidon's underwater palace. It is an underwater city inhabited by merpeople and their allies.
