Janice starts down this crawlway known as the Key Crawl since it is the key passage to reaching all of the Northwest passage from the main cave in Cumberland Caverns. The ceiling height is no more than 12 inches here. The crawlway goes for about 400 feet this way and continually gets muddier. At the end, you are on the edge of a canyon that seems to be about 80 feet deep. A tricky traverse gets you to the bottom and access to miles of cave.