Redditor RTWin80weeks was hiking along the beach outside of Lagos, Portugal when he came upon this amazing rock formation. It's a hole that goes deep into the earth--farther than he could see.
Other redditors claim to have been there. Ski6666 made this video showing the other side, which empties into the ocean. -SSS- thinks that this spot is at Farol Ponta Da Peidade, an area known for its exceptional natural beauty.
-via Twisted Sifter