The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

Enjoy dishes that founding fathers once ate at this Colonial Williamsburg pub.

An overlooked oasis of quiet on the grounds of Washington's monumental basilica.

Largest Roman Catholic church in North America.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

Gargoyle head that brings good luck.

A wunderkammer of gold and silver reliquaries and ancient saintly bones.

A full figure 4th century incorruptible saint lies in a glass coffin in Croatia.

An ancient knight and a symbol of the city's freedom.

When a supermarket opened up shop within a medieval building it became protected by UNESCO on a technicality.

A gigantic 10-foot tall stone man.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

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

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

This lovely tree was a thank you gift from the man known as "Public Enemy No.1."

Once part of a dam servicing an early 19th century grist mill, the tucked-way falls are a tricky-to-find urban oasis.

Baltimore's classic clock tower was once topped by a rotating, 20-ton medicine bottle.

Once America's tallest structure, now a Baltimore landmark.

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

A monumental statue of RCA's mascot now sits atop a historical society roof after a life of moving around.

This beloved Baltimore spot features caged dolls, a giant Pez collection, and many, many mannequins.

A museum dedicated to exhibiting remarkable outsider art.

It's not hard to see why the historic Peabody Conservatory of Music's library has been described as a "cathedral of books."

This free, take-a-book shop seems like a trick but isn't.