One man's journey to return a stone to its point of origin after 200,000 years.

Qatar's oldest market can trace its origins back more than a century.

Local lore says this 700-year-old tree has sacred and medicinal properties.

Built entirely of interlocking pieces, construction of this Chinese Muslim house of worship required zero nails.

This column celebrates Rome's victory over the Goths, and may be the oldest Roman monument in Istanbul.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

While you wait to cross the street at a traffic light in Mainz, you might notice that the light is staring back at you.

A bridge that has seen many reiterations over its lifetime.

You can spot this teeny tiny stained-glass window from the Bonifacius bridge.

Luxembourg's most popular statue since 1923 has been missing for... 26 years!

A neo-gothic statue modeled on German Emperor Kaiser Wilhelm II, which had its distinctive mustache shaved off by Nazis in World War II.

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

Perhaps the most spectacular grotto along the Algarve coastline.

The 28-foot granite map plots the locations of 40 theaters in New York City.

The highest tropical mountain range in the world is in Central Peru, home to a vast array of exotic and quirky plants and animals.

This "dead marsh" sits among the largest sand dunes in the world, a forest frozen in time.

A 250-year-old timepiece-automaton adorned with golden mechanical birds, which still sing to this day.

Legend has this precariously placed rock was placed by giants. Science has another explanation.

A stone marker and sculpture in the city of Riga stake a claim for the very first community Christmas tree.

This striking structure is the Socialist-modernist centerpiece of a former Soviet spa resort.

A monument to Poland's famous alleged UFO abduction case.

An enormous playhouse designed to look like 21 stacked Lego bricks, with another 25 million colorful Legos inside.

The ruins of an Estonian prison are drowning in the quarry lake where the convicts were once forced to work.