Canada's oldest railway tunnel is illuminated in a rainbow of color as it passes under the streets of this small city.

This top secret Chinese military megaproject is the world’s largest human-made tunnel structure.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

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

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

World's first "penitentiary," meant to be humane, drove men insane.

A dreamlike medieval church dug into the tuff rock, with unusual carvings and possible traces of the Templar knights.

Outstanding, eerie frescoes and decorations fill this 19th-century monastery.

The atmospheric ruins of a historic church can be found on a hill above the city of Oviedo.

In this brilliant blue spring in Germany, legend has it that a sad mermaid learned to finally laugh.

Rare recess caves fill this unbelievably beautiful Ohio park.

This tiny movie theater was the last one in the U.S. constructed in the Nuevo Deco architectural style.

Legend has it that Napoleon Bonaparte fell in love with this Gothic church.

An image of the legendary saint stands in the shadow of a cathedral she liberated.

Dating back to the second century, vestiges of prehispanic mural paintings are found in this underground palace.

Legend says this tiny ancient island is the lost ancestral homeland of the Aztecs.

An otherworldly alpine pasture with its own unique microculture that recalls Middle Earth.

Climb atop one of the world's longest and heaviest trains for an unbelievable journey across the Sahara Desert.

More than a million titles fill the labyrinthine shelves of this prestigious private library.

An eccentric garden of sculptures crafted in India decorate an Irish green space dedicated to Alan Turing.

An enchanting rocky island of scraggly baobabs surrounded by an ancient sea and sprawling salt pans.

This mesmerizing, colorful structure looks like a tent made from stained glass.

Charles Dickens described the concert room in this amazing Victorian hall as "the most perfect room in the world."

Parts of this sprawling temple complex are deteriorating, but its founder’s body remains intact.