This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

Looking strangely like Rome's Colosseum, this unfinished tower has dominated the skyline for over 100 years.

Displaced highlanders would take shelter from the wet Scottish climate under the large walled bridge at Glasgow Central Station.

This stately monument has been wearing a traffic cone hat for decades much to the delight of the locals.

The ornate structure is part of a building boasting more marble than the Vatican.

A small collection of objects of a bygone era hide in plain view.

Protecting the dead from opportunistic body snatchers.

The most loyal of little dogs, or a Victorian era publicity stunt?

Overlooked by many, the two famous Scottish warriors guard the main gate of Edinburgh Castle.

The final resting place of soldiers' loyal canine companions.

A six-ton wedding present for the King of the Scots.

Blighted Irish field and the ruins of a 19th-century cottage on the edge of urban Manhattan.

An institution dedicated to the towering buildings that make up skylines in New York City and around the world.

Twice a day one of these tragic bronze mariners drowns with the tide to remember all those the sea has taken.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

A popular European tradition makes its way to the states on one of America's most famous bridges.

John Hendrix predicted the creation of the "Secret City" built as part of the Manhattan Project.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Concrete strongholds stand guard over the Golden Gate.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

The oldest apple tree in the Pacific Northwest.

The magic's in the hole!

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

A sculpture of a salmon swimming through a brick building.