A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

This ruined fort and statue are a testament to the last king of Kaua‘i’s savvy diplomacy skills, which briefly brought Russians to Hawai‘i.

Football field-sized microalgae production tanks on the Hawaiian coast create a stunning view from space.

A model of a galactic embassy is hidden in plain sight along the highway, proposed by a UFO religion to find the aliens that created life on Earth.

A cooled lava flow from the Haleakalā volcano formed these surreal-looking columnar basalt structures.

A prehistoric landscape hidden in the cliffs of Maha'ulepu.

This angular brutalist playground turns playtime into modern art time.

Mai Tais and Navy Grog served up in one of the original tiki bars.

This building served as the first customs house in modern Greece.

This church combines Christian, Byzantine, and ancient Greek architectural elements.

The partially submerged ruins of a white marble quarry used in ancient Greece for over 1,200 years.

A solemn reminder of the infamous World War II war crime that massacred almost all the men in a small Greek town.

These ruins of a sacred Ancient Greek temple stand next to a luxurious modern resort.

The historic tower houses of this nearly abandoned Greek town have been compared to the spikes on an iguana's back.

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

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

Thousands of rusting train cars have been slowly falling apart on the edge of Greece's second largest city.

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

An ancient octagonal weather station named for the eight Greek gods of wind.

This half-forgotten fortress was constructed by the Ottoman conqueror of Constantinople.

Ancient serpentine sacrifice holder that has stood the test of time.

This crucial gathering spot along the "hippie trail" still displays old notes between traveling beatniks and backpackers.