A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

An ancient Egyptian temple in the middle of Madrid, Spain.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

The site of one of the strangest disasters in history—a wave of deadly molasses traveling at 35 mph.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

This supermarket is suspended 25 feet above an interstate highway.

An enormous, inside-out glass globe built in 1935.

The world's largest piece of copyrighted artwork.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

A men’s restroom became a sandwich shop.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

The site of Paul Revere's historic two lantern warning.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

This upscale streetwear store is hidden behind a fake Snapple machine in the back of a deli.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

A cluttered and astounding collection of antiquities and curiosities.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

Designed by Buckminster Fuller, this relic of the 67 Expo survived fire and ice.

This 1967 experiment in modular architecture was designed to be a new model for urban living.