A startling, centuries-old subterranean marvel hides in plain sight.

Ancient traditions and surreal birdwatching come into sharp relief along one of the world's most polluted rivers.

City law dictates that this mountaintop cathedral containing the heart of a saint is to remain the tallest building in town.

A community-run museum invites visitors to explore Jewish communities before and after the Holocaust.

Canada's largest graveyard boasts a lot of noteworthy artifacts as well as its own computerized mapping service.

Every year, the colorful murals of Montreal get a complete makeover.

Small ship votives hang from the vaulted ceiling of this port-side church with a Latin inscription on the wall.

A historic Montreal market that was the city's agricultural hub for over century.

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

Two thirds of this Montreal neon icon has survived to flash another day.

The vaulted ceiling is home to a scurry of “squirrelgoyles.”

Its columns were all carved from the same white oak tree.

Yale University's home for rare works, including the mysterious Voynich Manuscript.

A vast collection of rare books, manuscripts & extraordinary objects illustrating the history of medicine.

An archival collection of over 2,200 case studies which includes human brain specimens and tumor specimens.

The headquarters of the famous Yale society.

While many places make the claim, the Library of Congress says this restaurant is the birthplace of the hamburger.

One of America's oldest private membership libraries was long one of New Haven's best kept secrets.

137 graves holding New England's earliest residents.

An Aztec temple, the largest man-made pyramid in the world, sits buried in earth with a Spanish church set on top.

This cluttered cantina is famed for its cheese-spiked, raisin-flavored liqueur.

A 500-year-old series of tunnels long believed to be folkloric was uncovered beneath the streets of Puebla.

The splendor of this 17th century golden chapel has led it to be called the "eighth wonder of the world."

Hidden inside a hotel is a museum of miniature models depicting the traditions and history of Mexico.