Longshan Cave, which was originally a bomb shelter, is very cool. In fact, it is very ordinary, not a sight, but many people will come to Gulangyu to encounter it and pass it. The cave is long and the light inside is not very bright. It passes through the cave and is green. In the hole, you can often encounter a manpower board driver, because on the Gulangyu Island, you can't see any transportation except the tourist battery car, the cleaning car, and the patrol shop police car.