Minecraft wiki entry for Canyon, associated text: Canyons can connect to caves, dungeons, abandoned mineshafts, and any other generated structures. Due to the large surface area of their walls, canyons often have water and/or lava flowing down them (from springs in the walls, aquifers, or openings to the sea). A canyon that intersects a river, frozen river, or swamp is filled with stone under the body of water.