A geological mystery on Camelback Mountain.

One of the few guarded stops along the great spice route.

A "miracle" that seems to produce more holy fistfights than holy revelations.

A massive, heart-shaped, wind-carved crater in the middle of the Israeli desert.

A surviving remnant of the thick ice mass that once mantled most of Western Canada's mountains.

Few other hotels can rival the grandeur of the Castle in the Rockies.

Hoodoos, naturally eroded land formations, stand 20 feet tall in the Canadian Badlands.

Soaring over the Niagara Whirlpool since 1916.

A church that bred legends, and served as an inspiration for the Da Vinci Code.

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

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

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

Furniture tries to escape an abandoned building in San Francisco.

Where commuters walk through remnants of an ancient Greek necropolis.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A theatre built to house the rowdy Oxford graduation ceremonies became the stage for a debate about God's existence.

Scattered throughout London are ancient remnants of the city's former bounding wall.

In this cobwebbed old operating theater, you can practically hear the screams of the unanesthetized patients.

This legendary stone is of unknown origin, and throughout history has been a literal touchstone for British leaders.

Hear the quietest sound from across the dome.

What happens when a sculptor has to find a way around a 100-year-old copyright.

A working steam clock, one of only a few in the world, located in Vancouver's Victorian Gastown.

This bridge was constructed from the rubble of the infamous Bastille.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.