This story originally appeared on Travelandleisure.com.
One such location is Papafragas, a sea cave that hides a tiny beach inside its towering walls.
Once used as a hide-out for pirates, according to representatives from Milos' tourism board, the cave opens up to form a long and narrow fjord housing crystal-clear waters you can swim in between the scaling rocks.
The stairs can be extremely steep, according to the Greek National Tourism Organization, so take caution when climbing.
There are also boats that will take you there from the island's Adamas Port, allowing you to approach the beach by swimming through the narrow cave openings.
Get there in the morning and you'll feel as though you have the breathtaking swimming spot all to yourself.
While you're there, be sure to pay attention to the color of the water, as it tends to change from deep blue to green depending on the sunlight and temperature.
Once you've had a chance to take your cliffside swim, you can also explore the prehistoric settlement of Fylakopi, where you'll find volcanic structures that date as far back as 3,000 B.C.
The hidden beach is just one of the more than 70 top-notch beaches that you’ll find around Milos.