On This Day December 27

The Cave of Swallows in Aquismón, San Luis Potosí, Mexico is the largest known cave shaft in the world. The floor of the cave is a 1092 feet (333-meter)) freefall drop from the lowest side of the opening, with a 370-meter (1,214 ft) drop from the highest side. The first documented exploration was on December 27, 1966 by T. R. Evans, Charles Borland and Randy Sterns.

WANT MORE THINGS THAT HAPPENED ON DECEMBER 27? CHECK OUT MY ONTHATDAY BLOG. HERE'S A LINK