As a background to your cave adventure, you should probably know about speleothems, which are cave formations. The main types are stalactites that hang tight to the ceiling and stalagmites that might reach the ceiling one day. The formation of any speleothem takes an extremely long time. As each drop of water leaves a tiny amount of mineral residue on a cave ceiling, floor, wall, or other features, it adds to speleothem growth. When a speleothem is broken, it will not be replaced within our lifetime, if ever! Therefore, cavers must be extremely careful while exploring.