[Bonus Wednesday post as I try to catch up to my current travels!]

This high mountain area north of Oaxaca Mexico is the most biodiverse arid region in North America. I drove up the steep hairpin turns through thick fog, seeing how the mountains block rainfall up here. Mexico’s first biologist, Helia Bravo Hollis explored the area for years, documenting many new species, especially cacti. Thanks to her efforts, the rare biodiversity was recognized and protected, with a park in her name now the best place to tour the cactus landscape.

The diverse density of plants is far greater than Saguaro, Organ Pipe or Pinacate. There are also ancient marine fossils, rare snakes, insects and bats. We saw signs of a fox, and there are other mammals that live in the dry isolated valley. Many medicinal plants have been studied here too.

But the UNESCO site is also important for the Pre-Colombian archaeological sites. The oldest irrigation systems in North America have been found here. And besides growing crops like maize, drying pools were built to gather salt for trading. Salt was a high value trading good for centuries, connecting this harsh region with distant population centers.