This beautiful building in the heart of Manhattan's Financial District was empty for decades.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

A crumbling hospital from the 1850s on Roosevelt Island.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

This "City of Books" holds a museum, library, and the complete personal book collections of five of Mexico's greatest thinkers.

These biodiverse university gardens form a green oasis amid the urban chaos of Mexico City.

This crumbling Art Deco movie palace in Mexico City has been abandoned for two decades.

Explore the atmospheric ruins of an abandoned convent in the dense forests of Mexico's first national park.

Meant to be one of the most extravagant hotels in the world, now an eerie, abandoned architectural gem in Mexico City.

A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

Part bookstore, part café, and part forest.

Frida Kahlo's childhood home, now a museum of her life and works.

This hydrochronometer was invented by a Dominican monk and is a prime feature in this garden.

The only remaining arch of the oldest stone bridge in Rome stands in the middle of the Tiber.

Romans decided this 16th-century "talking statue" was so ugly, they named it after a primate.

A magnificent waterfall is also home to the remains of a Roman hydraulic engineering system.

The first Russian Orthodox church in the Catholic city of Rome in almost a thousand years.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

The spot where the fascist dictator made some of his most famous speeches including declaring war on Britain and France.

Museum dedicated to literary greats of the Romantic Period is also the home in which Keats met his untimely end.

This hill made entirely of ancient Roman jars was simply a garbage dump to the people of the time.

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

A fairy tale castle in modern Rome.