The steepest classic funicular in the world glides along a dizzying incline.

An exotic reptile facility showcasing some of the rarest, most venomous snakes in the world.

Why walk on this historical site when you can zoom down instead?

Dozens of lights dangle from the branches of what may be the brightest tree in Los Angeles.

A volcanic tunnel illuminated by natural skylights offers a shaded respite from the desert sun.

Sunset-colored dunes of volcanic ash make taking a poor photo impossible.

A Frankenstein blend of science and art allows one tree to produce 40 different types of stone fruit.

Mirrored floors and arched shelves create the illusion of an infinite tunnel of books.

A 1,500-year-old, 3-story subterranean city where ancient Persians took refuge in times of war.

Hundreds of glow-in-the-dark objects light up a museum in a historic zinc mine.

The medieval network of canals hidden underneath the city is opened to explorers each year.

The small sanctuaries lie just off the beaten path near one of Bhutan's most famous attractions.

Conspiracy theories and occult legends surround this mysterious natural rock formation.

The remains of a 1st-century aristocratic Roman town house featuring beautiful well-preserved mosaics.

The only microgravity tower in Europe can produce nine seconds of weightlessness.

The skulls and bones of thousands of soldiers line the walls of this small Italian chapel.

360° views of the city plus five floors of optical illusions and hands-on science.

Ancient structures used to make and preserve ice in the deserts of Persia.

One of New Zealand’s few castles boasts beautiful gardens, grand architecture, and a history filled with family drama.

Designed by Buckminster Fuller, this relic of the 67 Expo survived fire and ice.

17th century mosque for Shah Abbas' harem.

One of the largest Buddhist stupas in the world keeps an eye out in every direction.

The walls of the iconic dome are hollow and have a secret stairway.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.