This structure atop a craggy cliff in one of the most beautiful parks in Paris boasts an unbeatable view.

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

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

A simple plaque on the facade is the only reminder that the treaty ending the American Revolution was signed inside.

Shop at the 200-year-old store where Julia Child stocked up on copper cookware.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

An abandoned 19th century quarry in the middle of the woods, remade by unnamed wanderers into a massive series of rock thrones.

This stained glass window designed by Tiffany Studios is hidden behind the circulation desk of a public library.

The final resting place of President Chester A. Arthur and hundreds of others from Revolutionary War soldiers to poets, politicians, and painters.

This small-town Connecticut restaurant gives each diner a free book from its vast library.

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

This Parisian café is dedicated to great tea and the art of knitting.

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

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

A lavender labyrinth so large it’s visible on Google Earth.

A little-visited waterfall in an otherworldly landscape.

Visit the WWII bunker where the British won the battle for the skies.

Eclectic final resting place of the controversial explorer.

A museum wholly devoted to juvenescence.

The London pub overlooks where the Mayflower was moored before setting sail for the New World.

A commemorative plaque at the door pays tribute to an "American Patriot" known for his betrayal.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

This knockout museum lies in a sleepy corner of London.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.