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

Buenos Aires' city of the dead contains some very famous remains, including Eva Perón.

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

Op-art architecture designed for happiness.

This stunning concert hall has become a symbol of Iceland's national recovery.

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

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Medicinal spa created with the discharge from a geothermal energy plant.

This African beach is home to thousands of rare mainland penguins that are known for their annoying voice.

Not quite the menace it once was, this monster still has some chops.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

France's most famous cemetery, with some of its most curious tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

The famous artist couple lived and worked here, in two different houses separated by a bridge.

Frida Kahlo's childhood home, now a museum of her life and works.

The Boston square dedicated to the dark poet who was born nearby.

This one-time health resort was used by aristocrats around the world.

A church of bones, decorated with 40,000 human skeletons.

This bridge over the River Cuale leads to a neighborhood that was once an escape for Hollywood's elite.

This eatery transports diners to a place that no longer exists: East Germany.

This painted marvel is San Francisco's 400-foot ode to urban biking.

San Francisco’s century-old Christmas Tree.