Visit a surreal landscape so otherworldly NASA actually used it to train the Apollo 17 crew.

The chefs at El Diablo use heat generated by an active volcano to cook the food.

Where dogs like the rare "Fire-Tailed Border Cocker" run free on the mountainside.

Every year model trains zip through a miniature New York City that's now 150 landmarks strong.

This plot of old-growth forest is the largest surviving remnant of New York City's original woodland.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

A Dutch museum preserves the world's most diverse collection of vertical slices of soil.

Mined to a depth of 240 meters with a perimeter of about 1.6 km, the largest hand-dug excavation in the world.

A South African bar inside a hollowed out 6,000-year-old Baobab.

These curious caverns have been home to mushrooms, gangsters, and disco.

The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

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

The university library shaped like a giant piece of Swiss cheese.

This singular art museum in São Paulo is unique inside and out.

The building's fluid, wavelike walls are a true feat of architectural ingenuity.

Designed by Maya Lin, the memorial honors 41 individuals who died fighting for equal rights between 1954 and 1968.

Made famous by 'Star Wars,' these troglodyte homes face an uncertain future.

A mysterious "wedding cake" castle in the middle of the urban desert.

The oldest restaurant in Portland serves fiery coffee cocktails and an astounding amount of turkey.

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

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

The sister plane of the C-123 shot down during the Iran-Contra Affair has found a new purpose in retirement.

This grounded passenger jet is now a restaurant, complete with rows of seats and “flight attendant” servers.

Deadly scalding and one of the largest hot springs in the world.