An ethereal glowing blue ocean cave in Croatia.

An autonomous republic of Orthodox monks.

A fitting attraction for the corn capital of the world.

Crumbling necropolis set high above Fez.

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

The other side is actually green.

The courtyard of this small Marinid madrasa is a dazzling example of intricate Islamic architecture.

Traditional 11th-century outdoor tannery.

The final resting place of an unidentified revolutionary soldier sits behind a Virginia church.

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

Rowdy rebels fortified this home during the first popular uprising in United States history.

This once-palatial plantation may have been the site where a draft of the Declaration of Independence was written.

This museum explores the grim reality of life in the earliest British colonies in America.

America's first public mental health facility.

The innocent intentions of this monument are somewhat lost in the sculpture's muscled imagery.

The 28,000-year-old specimen is remarkably intact.

The first memorial dedicated solely to the Black troops who fought for the Union.

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

An overlooked memorial honoring the local Washington residents who died in World War I.

Look closely and you’ll notice that the color changes a third of the way up the tower.

One of the most influential presidents in U.S. history wanted only this plain, elegant monument as his lasting memorial.

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.