The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

The 19th-century pharmacy (now a used bookstore) was featured in James Joyce’s "Ulysses," and has changed very little to this day.

Locals dubbed it the "Owl Building" because of its bird-like appearance.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

Perhaps the most scandalous statue of America's first president.

One of downtown Berlin's last reminders of its Communist past.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

The upstairs reading room is packed with millions of rare books, literary manuscripts, and historical treasures.

Cold War intelligence agents monitored communist embassies from an attic in a former pigeon coop.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

The rogue roots are gradually consuming some of the historic marble grave markers.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

Tiny memorials honor individual victims of the Holocaust.

Just like the real 36th president of the United States, animatronic LBJ amuses visitors with jokes and stories.

One part antique store, one part curiosities hodge-podge.

The maze-like transportation hub contains abandoned areas, derelict stores, and a resident bat colony.

A monument to the man who almost killed Hitler.

It was once the base for a series of domestic terror attacks.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

The skyline of Montreal includes the silhouette of an unexpected fruit-shaped Canadian staple.

Montreal's giant farmer's market is a foodie's best friend, especially in the winter months.

This steep cable railway has been hoisting passengers in the heart of Québec City for over a century.