Wise spelunkers explore in groups, to prevent being lost or stranded in a cave. Spelunkers need reliable equipment, because the descent into a cave is like mountain climbing in the opposite direction. Basic spelunking equipment is similar to what mountain climbers use. Strong ropes make climbing possible and special tools attach ropes to cave walls. Special footwear makes it easier to explore hard-to-reach places, and hard hats protect spelunkers from falling rocks above. Caves are extremely dark, so spelunkers have to carry light sources (like torches and flares). One torch attaches to a spelunker's helmet so it is with him or her at all times. Caves are also very cold, so most spelunkers wear warm clothing.