A Hawaiian stairway to heaven—that you can't climb.

The untimely death of a dignitary's daughter led to this fort being abandoned before it was ever finished.

Legend tells how a Spanish soldier disappeared from this isolated sentry box without a trace.

Ancient and modern architecture are joined in Louis Kahn's monument to democracy.

This colorful palace is an oasis of calm amid the hustle and bustle of the Buriganga riverfront.

These medieval funerary monuments are now home to a colony of critically endangered vultures.

The bizarre headgear looks like it was made for a fool, not a king.

A charming Spanish village sits atop this natural limestone overpass.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

After millennia of erosion by sand and churning water this Brazilian valley now looks like a lunar fantasy.

A long, winding trek rewards you with a gorge so captivating it inspired a painting in the Tate.

Strange rock formations tower above the river that snakes through this enchanting Icelandic canyon.

Rare recess caves fill this unbelievably beautiful Ohio park.

This extraordinary geological oddity resembles human-made pavement.

An ancient Scottish rock formation said to be the gravesite of a giant remains ensconced in legend and intrigue.

Islanders once used this dramatic, otherworldly landscape to hide their cattle from Viking raiders.

Largest cave system in Africa.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

This vertical pinnacle in China was the inspiration for the floating mountains in the movie “Avatar.”

The land is full of geologic eye candy, such as otherworldly spires, mushroom-shaped hoodoos, and prehistoric fossils.

After years of slow decline, a derelict Gothic castle is now being restored to life.

An Ethiopian "Jerusalem" featuring a church hewn out of a single rock.

Massive stele returned to Ethiopia after 70 years in Rome.