A campsite structure is a type of shelter used when camping outdoors. The two most common types of campsite structures are tents and leantos. A TENT is a lightweight, portable shelter made of fabric or other material stretched over poles and secured to the ground. A leanto is a more permanent structure, usually made of wood, with a roof and open sides. Both tents and leantos provide protection from the elements and offer a comfortable place to sleep while camping.