The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

A house carved into a rock in the 1940s.

Visitors to this library are in for a real-world education in modernist architecture.

Despite its name, this route in southern Utah offers a heavenly day trip.

This raised bulls-eye visible from space was the subject of an intense geologic controversy.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

The celebrated eyesore created by starry-eyed sweethearts.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

The ruins of an abandoned medieval city where the last Byzantine emperor was crowned.

This 15th-century island fortress later served as home to the executioners no one wanted to live near.

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

Large collection from the 3rd millennium BCE.

This gem is often wrongly overshadowed by the larger, newer Metropolis church in Athens.

150 or so scrounged-up lamps, chandeliers, and lanterns light up this alley in central Athens.

No one is sure if the world's fourth-largest diamond had been found in a rubbish heap or was pawned by Napoleon's mom.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

Trick water gardens from 1619 featuring a 200 piece mechanical theater powered by water.

The beautiful, ornate weather station is the most popular geocache in Salzburg.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

One of the most controversial statues in Romania is an emperor with no clothes.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

Romania's triumphal arch looks out over Bucharest.