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

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

Three columns of volcanic rock shoot out of the ocean.

A black sand beach where glacial fragments wash ashore and look like sparkling diamonds.

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

An artificial date palm stands as a memorial to Warsaw's Jewish community.

A collection of modern and vintage pinball machines housed in the cellar of a 15th-century building.

Seven dragon statues—including one that breathes real fire—are scattered throughout the streets of Krakow.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

An underground city of salt.

One of the best-preserved medieval streets in Europe.

Swarms of dainty flying insects swarm into the Petaloudes Valley to get busy.

A dark, narrow tunnel that leads to a charming lake and waterfall.

Nature puts on a spectacular show at this blowhole on the eastern side of Gran Canaria.

Hundreds of caves once used to store grains and animal feed.

Museum dedicated to the terror regimes of Hungary.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

The "dragon babies" of southeastern Europe.

A miniature train-ride through Slovenia's largest cave system.

Gargoyle head that brings good luck.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

A Nesting Doll of Churches.

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