A winding drive (not for the faint of heart) brings you back to a "stuck-in-time" era: an oasis surrounded by cacti and agave. A simple reminder that water is a precious resource, especially in the dusty desert region in the Mexican Sierras of Oaxaca. Just beside the pools, the "frozen waterfalls" formed from limestone drop off the vertical cliffs. There are only a few tiny holes where water fizzes out into the pools to keep them flowing full. WARNING: don’t get too close to the slippery edge... It’s a long way down, but the cacti are always there to catch you.