Endless Dread: The Mysterious Lagoon
The waters of Brazil's Lagoa Misteriosa, or Mysterious Lagoon, are so clear, looking down you might expect to see the bottom — except for the fact that its bottom has actually never been found.

The waters of Brazil's Lagoa Misteriosa, or Mysterious Lagoon, are so clear, looking down you might expect to see the bottom — except for the fact that its bottom has actually never been found.