A little-visited waterfall in an otherworldly landscape.

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

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

This elegant arc of a waterfall marks a religious turning point.

The most powerful waterfall in all of Europe.

Strange rock formations tower above the river that snakes through this enchanting Icelandic canyon.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

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

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

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

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

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

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

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

Baroque celebration of the end of the Great Plague of Vienna.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

Eighty million natural history specimens call this gargantuan museum home.

The world's largest model of our planetary system.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

It houses the remains of a 17th-century version of the Titanic.

The yawning maw of this pagan visage is said to bite off the hands of liars.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.