The Cave of Swallows is one of the biggest natural depths of the world located in the town of Aquismón in the state of San Luis Potosi (Mexico). The depth of the abyss is about 376 meters, a Tour Eiffel could fix inside it. The top has a diameter close to the 60 meters, while the bottom has an aperture of nearly 300 meters. It has the characteristic of having the aperture smaller than the bottom, giving it a conical shape overall.

The name “swallows” is due to the habitants of the region, who were the first to saw the unique phenomenon that happens every day in its interior: thousands of birds of the family of swifts, which the locals call “Swallows” leave the bottom of the abyss, filling the sky with their flight from the Huasteca, which is repeated in the evening when all the birds return to the cave indicating that, one more day is over. In the cave is also possible to find a species of parrots, called locally Cotorras de la cueva (Cave’s Parrots).

The history of the Cave of Swallows started at 1976, the year the cave was discovered by a team of ornithologists from the University of Texas, who made a detailed survey of birds in the Huasteca potosina area.

Currently, the Basement of Swallows is highly frequented by lovers of climbing, base jumping and spelunking; its beauty and uniqueness makes it one of the largest protected natural areas of Mexico.