Top 10 mysterious historical sites in the world

Underwater Pyramids in Portugal

In 2013, a gigantic underwater pyramid was discovered by a fisherman in the Azores, an autonomous region belonging to Portugal. Located about 1,500 kilometers west of Lisbon, the structure measures 60 meters in height.

An intensive exploration launched by the Portuguese Navy is underway. It's believed that the pyramids may be a vestige of the lost city Atlantis, an advanced legendary prehistoric civilization. Records depicting the mythical Atlantis first appeared in writing by the Greek philosopher Plato in his dialogues of Timaeus and Critias. According to Plato, by in about 10,000 BC, all of Atlantis was swallowed by the ocean "in a single day and night of misfortune".