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

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

America's oldest Eastern European synagogue provided the immigrants of crowded Lower East Side tenements a space of sanctuary.

New York City's only preserved family home from the 19th century.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

A 125-meter long "tribute to the Brazilian people."

Built for the 1962 World Cup, this fully functioning botanical clock is still ticking.

Pivotal home of Nobel Prize winner Pablo Neruda.

Golden Gate Park's historic collection of plants.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

This magnificent castle grew from a small Moorish fortress, and reportedly inspired two iconic Disney castles.

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

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

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

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

Remains of the artificial harbours invented for the Allied invasion of Normandy can still be seen at sea.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Its sunny hues are believed to have inspired the town's color palette.

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

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

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

A Christian monastery stands on what was once a holy Incan temple.