If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

Iceland's largest lagoon is home to stunning multi-colored icebergs.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

Medicinal spa created from the mineral-rich runoff of a geothermal power plant

The first tunnel to be dug beneath a river, repurposed as an art and museum space.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

The handiwork of a underdog clockmaker who solved an impossible problem for an Empire, and forever revolutionized seafaring.

A unique tribute to the millions of animals who served and died for the British military.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

The barrel-made lookout from Shackleton's final ship is tucked away in the crypt of one of London's oldest churches.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

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

Commonly acknowledged as the only public monument to the Devil himself.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

The earliest known map to show America, discovered by accident at a Paris bookshop.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

An ancient Egyptian temple in the middle of Madrid, Spain.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

Part of the medieval watchtower is displayed in an otherwise ordinary parking garage.

A rare set of strings by famed instrument maker Antonio Stradivarius is on display in the Royal Palace.

Once a strategically imperative naval base, portions of this Bermuda dock complex now serve cruise ships.