Puerto Rico's oldest rum producer started its 140-year-old business with "a little barrel."

Legend tells how a Spanish soldier disappeared from this isolated sentry box without a trace.

This former sugarcane transport tunnel is now a portal to a lovely beach.

This limestone cave offers an incredible view of the Río Grande de Arecibo valley.

The bat-covered home of one of the world's most popular brands of rum is located on a tropical Art Deco campus.

This chapel on a cliff is renowned for its healing powers and was founded on the site of a supposed divine intervention.

The world's second largest single-dish radio telescope, once used to contact E.T.

This small primate research island is teeming with playing, fighting wild monkeys.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

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

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

The curious underground history of keeping Paris clean.

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.

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

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

Scenic mount trashmore, Virginia Beach's most curious waterfront still has a couple of secrets.

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

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

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

Fittingly, America's museum of architecture is itself a magnificently designed old building.