A perfect turquoise lake colored with glacier dust.

A bright little alley in La Boca is a part of tango history.

A series of waterfalls so massive they straddle the border of Argentina and Brazil.

What happens when you cross a mayor and a painter?

This ominous Albanian fortress houses tanks and downed planes as a reminder of their victories over Western imperialism.

An Albanian monument to the Communism that nearly crushed the country is now a crumbling wreck.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

This South London cemetery holds the remains of more than 15,000 people.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

The world's largest bicycle shelter can hold more than 12,500 two-wheelers.

Portugal’s highest lighthouse has one of the most impressive focal planes in the world.

Ring the bell to enter a bar that looks equal parts museum and old curiosity shop.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

This historic covered bridge contains a series of macabre paintings that communicate one thing: everyone dies.

The alpine falls where Sherlock Holmes apparently met his demise can actually be visited.

Legend says if you stick your thumb in the hole and it gets wet, your wish will be granted.

Roman ruins, natural methane fires and a lovely beach.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

This famous city eluded concrete detection until the early 2000's.