No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

These azure waters were thought to lead to the Mayan Underworld.

Found down a long dirt road, a sacred Mexican cenote and 18th-century hacienda remain hidden.

If you can look past the nearby sewer pipes, this urban sinkhole grotto is a mini-paradise.

Still standing despite its considerable slant, this tilted lighthouse has become a local symbol of resilience.

At least seven hues of blue and turquoise make this freshwater lagoon unique.

A Byzantine-era church hidden in a wooded area below the Acropolis.

This striking sculpture of Icarus honors Greece's fallen flyers.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

What once sat in the world’s spotlight is today a largely disused ghost complex.

A sharp sculpture made of thousands of pieces of jagged glass.

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

The ruins of an abandoned medieval city where the last Byzantine emperor was crowned.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

The highest peak in all of England is plagued by dangerously fickle climate shifts.

Huge winged monument in the United Kingdom.

The highest peak in Wales is said to be the final resting place of a giant killed by King Arthur.

This sculpture of disembodied body parts forms a poignant memory of the horrors of World War II.

A poetic monument to the Scottish Parliament.

Poetic, metallic giraffes adorn a square off an Edinburgh thoroughfare.

An artist's whimsical transformation of everyday objects.

Enter this small nook and you'll be surrounded by 360 degrees of street art.

The colorful stairs are made with marble from the world's major quarries.

Touching this 18th-century Scottish philosopher’s toe allegedly conjures good fortune.