This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

The only natural lake in the world that drains into both the Atlantic and Pacific Oceans.

An architect's childhood fantasy treehouse made real.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A beautiful geyser under environmental threat.

Twisted buildings adorn the banks of the Rhine river.

This futuristic German television spire is actually the world's largest digital clock.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

Elaborate tile work in this railway station tells the story of Portugal.

The stunning interior of this Gothic church is covered in ornate gold details.

Ancient catacombs form the foundation for this Rococo orgy of a church.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.

The largest cemetery in Louisville is the final resting place of Col. Sanders and Muhammad Ali.

One of the oldest of its kind.

A pride of the state, this working museum crafts pottery mosaics in the style of Pennsylvania's earliest European settlers.

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

This elaborate towering structure was once famed for its revolutionary height.

This stone tower marks a lookout point over the historic Washington Crossing, and maybe some buried treasure.