From the Super Mario Wiki
Ads keep the MarioWiki independent and free :)
Conkdor Canyon, or World 2-1, is the seventh regular level of Super Mario 3D World and the first one in World 2. It is unlocked via completing Bowser's Highway Showdown or by the secret warp in Koopa Troopa Cave, and its own completion unlocks Puffprod Peaks and Shadow-Play Alley. It is set on an old-looking building and introduces Conkdors, the main enemies in here. Conkdor Canyon also appears in Captain Toad: Treasure Tracker if the player's Wii U has save data for Super Mario 3D World.
The first area contains a few Conkdors and Stingbies, as well as some ponds of quicksand and Jump Panels. Just after the third Conkdor encountered, atop a wall behind it there is a Warp Pipe that leads to a room with a golden P Switch. The Checkpoint Flag is found near a small oasis with grass, and small pond with coins in it, a palm tree and a Conkdor.
Next, Mario must cross a bridge made of moving tiles, and then another bridge, this time a very narrow one, guarded by more Conkdors. The last part contains more Stingbies, a quicksand fall, and a long shifting bridge that leads to the Goal Pole.
Super Mario 3D World
The hidden Luigi is painted on the wall beneath the first shifting bridge, more clearly visible when looking through the binoculars the Sprixie provides to the right of the Checkpoint.
Captain Toad: Treasure Tracker
8-bit Luigi can be seen behind the stage from the platform with the Gold Mushroom.
Names in other languages