The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

Geothermal waterfalls in Tuscany.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

Stalactites and stalagmites in a beautifully lit cave.

Thousands of well-dressed mummies below a monastery.

Renaissance villa and gardens complete with a tormented colossus.

Pompeii's less famous neighbor is still revealing her secrets.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

An alchemist's "magic door" stands in the middle of a Roman park.

A celebrity from the late Cretaceous period.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

A super-sized promotional trick that is now a D.C. landmark.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

Home to items never before seen by the public.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

The site of the climactic scene from the classic horror film is now a historic landmark.

A cluster of headless, armless sculptures looms within a popular Polish park.

An impressive monument to Poland's independence.

One of the largest amphitheaters in Europe is a former Nazi gathering place that still stands today.

This open-air museum was originally a World War II testing ground for German missiles and rockets.