A monument celebrating the idea of reaching inaccessible places.

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.

The New York hotel where tragic visionary Nikola Tesla spent his final hours, destitute and alone but for the pigeons.

Elevated freight railway turned wildly successful urban park.

After starting as a whimsical tourist attraction that eventually found its way to ruin, these renovated canals offer a lush and exotic locale on the Pacific Coast.

This abandoned seaside fortress is now simply an imposing ruin being taken back by nature.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

This failed condo development was reborn as a street art hub.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

The design of the Palacio Salvo has been described as "a lighthouse on top of a building."

Visiting dignitaries and Hollywood stars once stayed at this 1920s hotel, alongside ghosts that are said to haunt its corridors.

Now containing the bones of the actual conquistador, instead of someone else.

A backdoor to Machu Picchu that only the most foolhardy infiltrator would attempt to breach.

This Peruvian canyon is filled with geometric salt pools that have been being harvested since the Incan empire.

Huge stone depressions which may have acted as an Incan agricultural experiment.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

This Balinese sea temple is thought to be guarded by the hundreds of monkeys that live around it.

Isolated atop this Balinese sea crag is a lovely Hindu temple that is said to be guarded by sea snakes.

Singapore's landscaping project is home to 18 incredible Supertrees.

Holy Hindu shrine in an enormous, monkey-filled limestone cavern.

A bright little alley in La Boca is a part of tango history.