Playa del Amor (Hidden Beach), Mexico
An underground or hidden beach may sound like a stuff of local legends, but it’s actually true. The hidden beach of the Marietas Islands was once used as a military testing ground in the early 1900s by the Mexican government. It’s believed that a bomb was responsible for creating the crater in which the beach is hidden in.
You can access the beach either via swimming or kayaking through a long tunnel. Be careful, though, as the sea is quite rough and the rocks can be quite treacherous. But, the place is well worth the hassle, more so since there’s the occasional humpback whale spotting on the way.