Seven parks are undeveloped with no facilities: Allegheny Islands, Benjamin Rush, Bucktail, Erie Bluffs, Prompton, Swatara, and Varden; the last four of these are in the process of being developed. Five state parks are small picnic areas: Laurel Summit, Patterson, Prouty Place, Sand Bridge, and Upper Pine Bottom. Five state parks have major U.S. Army Corps of Engineers dams and/or lakes: Bald Eagle, Beltzville, Elk, Kettle Creek, and Sinnemahoning. Three former parks now belong, at least partly, to the U.S. Army Corps of Engineers. Seven parks preserve the industrial past: Canoe Creek is the site of a former lime kiln, and Caledonia, French Creek, Greenwood Furnace, Kings Gap, Mont Alto, and Pine Grove Furnace (plus one former park) are all former iron furnace sites. Eight current parks and one former park contain at least part of eight different National Natural Landmarks.