The Cave of Swallows
In the Mexican jungle, a hole in the ground drops 370 metres into darkness. Every dawn, thousands of birds spiral up out of it, and every dusk, they dive back in.
What was reported
The Sótano de las Golondrinas, the Cave of Swallows, is a vast, open shaft in the forest of San Luis Potosí. Its mouth is about 50 metres wide, and the drop to the floor is around 370 metres, deep enough to fit a skyscraper inside.
Every morning, huge flocks of white-collared swifts and green parakeets fly up out of the cave, circling round and round the walls to gain height. At dusk, they return, folding their wings and dropping into the hole like stones.
Explanations offered
The shaft was formed over millions of years as water dissolved the limestone. It's one of the deepest open-air cave shafts in the world. The local community now manages access, limiting rope descents and BASE jumps so as not to disturb the birds.
- When
- Explored from 1966
- Where
- Sótano de las Golondrinas, San Luis Potosí, Mexico
- Witnesses
- Cavers, BASE jumpers and the local Huastec community
- Status
- A real place
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.
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