Crystal Crossing (Japanese: だいすいしょうのみち Big Crystal Road) is a dungeon in Pokémon Mystery Dungeon: Explorers of Time and Explorers of Darkness, and Pokémon Mystery Dungeon: Explorers of Sky. It is unlocked after clearing Crystal Cave, which was unlocked by turning the three crystals blue. It has 13 floors (14 if Crystal Lake is included). Crystal Lake is where the player battles Grovyle on their first visit. After the end credits, Azelf will be the boss and will be recruited upon defeat.
There seems to be no connection to items and floor.
Along the way though this dungeon, players will encounter the same traps as they did in Crystal Cave.