Carvings in Turkey's Marble Road may have directed ancient Romans to a hidden brothel.

The ancient latrines of the Greeks, in all their public glory.

1513 Turkish world map, full of European state secrets and snarky commentary.

This famous city eluded concrete detection until the early 2000's.

Roman ruins top white travertine terraces formed by ancient hot springs.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.

A miniature city, once ruled by the Queen of the Netherlands.

The Netherlands' first car tunnel has an unusually rectangular shape.

This hotel was once home to a steamliner company and became the final rest stop for Europeans heading to the New World.

Old ships and machinery fill a historic harbor in the city that's home to Europe's largest port.

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

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

The housing complex served as an anti-fascist fortress during the Austrian Civil War.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

Op-art architecture designed for happiness.

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

Legend says if you stick your thumb in the hole and it gets wet your wish will be granted.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

A marvel of Byzantine engineering under the streets of Istanbul.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

Ecuador’s historic seat of government has been quietly looted in recent decades, and no one knows how or by whom.

A short volcanic hill in Quito doubles as a stellar observation point of an iconic statue.

This huge green space packed with activities will make you forget you're in the middle of the Ecuadorian capital.