A magical world of elves and fairies tucked amongst the trees in Colombia.

A 10 million-ton rock once worshiped by the Tahamies Indians, accessed by an astounding staircase.

Enchanting cave with a river crashing through the roof.

The caldera of this mini-volcano has been turned into a naturally heated mud bath.

Towering high above the neighborhood of La Candelaria, the church is easily recognizable by its distinctive red-and-white striped facade.

San Franciscans leave gifts and messages for the magical beings that live behind the tiny, mysterious door installed on a tree in Golden Gate Park.

San Francisco's oldest surviving monument and meeting place for 1906 survivors.

Olfactory delights in San Francisco's Botanical Gardens.

This private residence was the template for one of the most beloved television homes of all time.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

This shop specializes in oddities and Victorian-inspired wonders.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

A huge musical instrument played by the ocean.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

Now famous as the "Harry Potter bridge," this impressive concrete viaduct has long been an icon in its own right.

The highest peak in the United Kingdom has a history of physics, specters, and a pilgrimage of strange objects.

Spend the night in this formerly abandoned traditional Scottish village.

Amazing and mysterious Neolithic settlement on Scotland's Orkney Islands.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

This series of Scottish caves has no clear purpose other than baffling historians.

The hellish conditions of this abandoned mine that snakes beneath the Pacific Ocean gave it its diabolic name.

The largest geyser field in the southern hemisphere is a spectacular sight.