Cristian Dimitrius and Fran Hutchins have observed thousands of bats here, as their den in San Antonio, Texas, left and flew into the sunset…

Bracken Cave is the summer home of the world’s largest bat colony. With millions of Mexican free-tailed bats living in the cave from March thru October, Bracken holds one of the largest concentration of mammals on earth. The emergence of these millions of bats, as they spiral out of the cave at dusk for their nightly insect hunt, is an unforgettable sight.

GoPro: One Million Bats