A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

A marvel of Byzantine engineering under the streets of Istanbul.

A statue in Budapest's Liberty Square honors the former U.S. president's efforts to end the Cold War.

This massive blockhead sculpture hides an entire library.

The video game-themed street art first popped up in the French city.

The curious underground history of keeping Paris clean.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

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

France's national museum of scientific and industrial instruments.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

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

The vast, legendary catacombs hold secrets much stranger than stacked bones.

France's most famous cemetery, with some of its most curious tombs.

A mailbox that saved a nature reserve.

Walk through the history of American pop culture.

An allegorical sculpture in Maryland wears the artist’s politics on its trunk.

The world's oldest continuously operating airport was founded by the Wright Brothers.