The Pit - IMDb

While hiking in an isolated forest, survivalist Danny Coile (Les Stroud) and old Army buddy Arron James (Stacy Brown Jr.) become hopelessly trapped when they fall into a deep dark cenote with steep walls and no way out. Over the next 85 five days, they transform from mild-mannered old friends into vicious, bloodthirsty animals willing to do whatever it takes to survive.::thomas smugala