Paleoamericans built these ancient walls high in the Colorado Rockies as part of an extensive hunting system.

This tea house was a hand-built gift from Boulder's sister city in Tajikstan.

The highest paved road in North America winds its way up Mount Blue Sky in Colorado to an altitude of 14,130 feet above sea level.

Lost subway station nestled beneath Toronto's busy commuter line.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This 16th-century house tells the city's history through old artifacts and quirky tales.

Largest lake in Great Britain measured by surface area.

This Scottish bridge seems to compel dogs to leap to their death.

Amazing and mysterious Neolithic settlement on Scotland's Orkney Islands.

This hidden park hosts a rogue’s gallery of eccentric architectural obelisks.

A massive Montreal stadium that has seen nothing but trouble since its inception.

The biggest museum dedicated to insects in North America, one of the largest in the world.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

This 1967 experiment in modular architecture was designed to be a new model for urban living.

The walls of Germany's Parliament still show the scars of the Red Army takeover in World War II.

The largest bell in the world has been swinging high above a Cologne cathedral for almost a century.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

A Christian monastery stands on what was once a holy Incan temple.

Built on the remains of one the Incas’ most important gathering spots, this square keeps the spirit of a fallen empire alive.

This geometric feat is a testament to the Incas' mesmerizing architectural abilities.

This small oxbow lake has rare giant river otters and some Seussian-sounding birds.

The little bear in the "funny kind of hat" has made his way from London back to Peru.

The large collection of pre-Columbian pottery might make you blush.

Visiting dignitaries and Hollywood stars once stayed at this 1920s hotel, alongside ghosts that are said to haunt its corridors.