Treasure Planet, as well as being the name sake of the film, is the trove of pirate Captain Nathaniel Flint's treasure. The planet is surrounded by two planetary rings that form an X shape, marking X for treasure. The entire planet is discovered to be a giant machine, developed many years ago by an ancient civilization, and is used to hide and protect Flint's treasure in the center of the planet. The only access to the center is by way of a portal door. However, once entered, a booby trap is triggered for the entire planet to explode; this is intended to destroy both the treasure and anyone who wants to take it. Fortunately Jim manages to use this portal door as a means of escape only seconds before the planet ruptures.