These barriers stand as stark reminders of Northern Ireland's troubled past.

Hidden in plain sight on a gable between two towers on the roof of shipping firm F. Laeisz' headquarter in Hamburg sits an unexpected bronze sculpture.

This 600-year-old home seems to defy physics.

See some of the world's greatest racing horses at this idyllic thoroughbred breeding facility and garden complex.

This monument marking the center of Mexico might be more political than geographical.

After several moves across Mexico City, these two statues found a home in Mestizaje Park.

Come face to face with the ferocious visage of the serpent-headed mother goddess of the Aztecs.

This museum houses two of Mexico's most impressive Aztec monoliths.

Once home to an aristocratic family and a workers' organization, this intricately tiled building now houses a chain restaurant.

Inside a busy metro station, an impressive mural depicts the prehispanic city of Tenochtitlán.

Diego Rivera hid various people and symbols in his first large-scale mural project.

These spectacular, symbolic serpents lie within the shadow of the Great Temple.

Mexico City's largest market contains a Willy Wonka-esque wonderland.

These haunting ruins of a 700-year-old Prehispanic city have witnessed centuries of wars and massacres.

A disquieting Aztec sculpture displays hundreds of stone skulls representing the victims of human sacrifice.

Frida Kahlo's childhood home, now a museum of her life and works.

This bridge was constructed from the rubble of the infamous Bastille.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

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

This vibrant side road in Doha was painted light blue to reduce heat.

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

An architectural oddity hides in plain sight on this iconic London bridge.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.