Fire swamp

A fire swamp is a dangerous forest mentioned and featured in The Princess Bride.

Physical description
In the book, fire swamps are mentioned as being misnamed; they are swamps containing lush trees standing a giant height, casting shadows on the ground; the swamps also with a large percentage of sulfur and gas bubbles which spontaneously combust. Because of the darkness, fire swamps are also moist.

Fire swamps often have holes that shoot jets of flame and pools of sinking sand. They are also home to rodents of unusual size.

The largest known fire swamp measures 25 square miles, and is located in Australia, a day away from the city of Perth. The fire swamp between Florin and Guilder is about a third the size of the Australian fire swamp. It took Westley and Buttercup six hours to navigate the swamp.