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

Along this wire fence, travelers have been leaving a particular memento since 2012.

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.

Inside this Icelandic greenhouse, geothermal energy keeps tomatoes warm and growing.

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

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

The floor of this spectacular Baroque sanctuary is covered in memento mori.

Hans Christian Andersen for the postmodern world.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

Site of the first radio and telephone broadcasting companies in Copenhagen.

Copenhagen's celebrated theme park and gardens.

This pair of gilded girls atop an Art Deco building in Copenhagen were built to function as a weather indicator.

Those who own or stay at this 500-year-old, allegedly cursed house often meet terrible fates.

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

These slanted cubic abodes are a creative if odd solution to a zoning pickle.