It probably started small. Maybe a gopher dug a burrow, or perhaps the foot of a donkey broke through the ground. However, over the years, rain and gravity have grown that small hole in the roof of a sea cave on the coastline of Mexico to enormous proportions.
The hole, which is now surrounded by a rope fence to keep people from falling in, is roughly 200 feet across and 80 feet deep. Known as La Lobera, the hole looks down into a sort of underground beach, which has now been populated by sea lions. They seem to enjoy lying in the shade of La Lobera very much indeed.
There is a nearby restaurant, and one can camp along the beautiful coastline for only a few dollars.