The Chasm is a giant pit that leads straight down to the bottom of the land and connects with the Subterranean Lake. This stands as your first major barrier to progression, requiring you to build a stable bridge to make your way across in order to gather Red Ferns.
If you fall down it, whether by accident or by your own choice, there is a significant chance there will be water to break your fall, as the bottom of the map consists entirely of water which makes up the Subterranean Lake.