The secret city built by the Manhattan Project.

Moonbows over Kentucky.

Cliffs that hold fossils, including the earliest known reptile, dating back more than 300 million years.

A pilgrimage site where people ask Saint Dymphna to watch over those who are not of sound mind.

An underwater restaurant, surrounded by a coral reef.

This series of Armenian caves held the oldest brain, shoe, and winery in the world.

Right up until the 20th century this network of man-made caves was the biggest village in Eastern Armenia.

Megalithic monuments resembling magic mushrooms.

At 8,000 feet, the world's highest tea estate draws visitors for both its products and its panoramic views.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

Devastated landscape used for hundreds of years by the Romans as their primary mining site.

Ottoman-era houses lovingly preserved.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

A small Portuguese cottage formed between boulders in the countryside.

An ancient tomb that still stands in Portugal.

Houses are tucked between, on, and underneath giant boulders.

A museum devoted to bringing to light forgotten or neglected histories through exhibitions, education and public programming.

Africa's Venice on stilts.

Divinely-inspired village houses 6,000 dolls, plus strange and lovely outsider art.

Garden dedicated to native carnivorous plants and site of huge flytrap heist.

Pull up and have a drink at a museum filled with hundreds of years worth of shipwreck artifacts.

Home to the world's oldest functioning orrery.

A Buddha-filled cave that is named after a giant monster spider.

Frida Kahlo's childhood home, now a museum of her life and works.