The last remnants of a massive medieval wall that once encompassed the city of Berlin.

The only thing sweeter than the potatoes is the canine proprietor of this roadside stall.

An imposing Omani fortress surrounded by date palm trees.

This spectacular mosque houses the second-largest chandelier in the world.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

On any given day this sprawling market houses literally tons of government-regulated gold, gems, and precious metals.

Planned as the world’s first zero-carbon city, it had lofty ideals—but is only 5 percent completed and aiming for 50 percent carbon-neutral.

The largest fountain in Bratislava.

Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

The remains of the second-oldest zoo in Europe can be seen within these library gardens.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

This amazing abuela became a diehard metal fan late in life and an icon of Madrid's '80s rock scene.

A whimsical brother of the nearby Fallen Angel statue takes the falling part quite literally.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

Commonly acknowledged as the only public monument to the Devil himself.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

An ancient Egyptian temple in the middle of Madrid, Spain.

The spot where the two men ate together now stands enclosed in glass.

Lie in a hammock where George Washington stood.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

An abandoned shopping gallery built during Fascist Italy tucked in the center of Palermo.

A study of Fascist era Art Deco design in Italy.

Haunting graffiti left by prisoners of the Spanish Inquisition.