Grutas de Coyame

The Grutas de Coyame are a show cave in the dry hills of the Chihuahuan Desert, in the municipality of Coyame del Sotol in the northeast of the state. The entrance sits partway up a mountainside beside the free highway from Chihuahua city to the border town of Ojinaga, at about kilometer 135 and a few kilometers from the small town of Coyame. Depending on the route and the source, the drive from the state capital is given as 120 to 142 kilometers, roughly an hour and a half.

The caves formed in marine limestone, and the rock still holds fossils of corals and ammonites from the old sea floor. Over millions of years water seeping through it deposited calcium carbonate as stalactites and stalagmites, along with aragonite crystals that grow in odd geometric shapes. Inside, the route descends about 84 meters and covers some 1,330 meters through 17 chambers and passages with names like Sala del Santo Niño, Pasillo de Pátula, Camposanto, Purgatorio and Infierno. The temperature stays around 22 °C all year.

The caves are carefully managed by the municipality. The entrance door stays shut except when a group goes in, to keep humidity and temperature stable, and the lights are switched on section by section as the guide leads the group forward, then turned off behind it, so the formations spend most of their time in total darkness. Tiny, colorless cave crickets used to live in the developed passages but seem to have disappeared. Tours begin in the Salón Oriental with a short talk on how the caves formed and last about an hour and a half. Coyame itself, founded as a Franciscan mission in 1715, is known for sotol, the regional agave spirit that gives the municipality its name.