High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

The oldest stone house in Paris was built by its most famous alchemist.

This massive library holds what was once the largest book collection in the world.

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

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

Try not to get slimed in Tribeca.

Built in the 1920s, this co-op in the Bronx feels more like an Italian villa than a typical New York apartment building.

During the American Revolution, this mansion hosted failed peace talks between the British and Americans.

The Underground Railroad passed right through this historic Brooklyn Heights church.

The origins of midtown Manhattan's anachronistic wooden farmhouse remain a mystery.

This Manhattan museum houses one of the largest collections of Spanish art and manuscripts outside of Spain.

A hidden architectural treasure in New York's Brooklyn.

This curved Manhattan building was built to house the opulence of John D. Rockefeller's oil empire.

Imagine having a street run right through your home, or better yet, a historic bridge three stories high.

The notorious headquarters of a corrupt political machine.

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

A historic 1890s architectural masterpiece with an iconic clock tower that, once open to the public, now faces an uncertain future.

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

A discreet little stairway on St. Nicholas Avenue leads to a quaint and unexpected cobblestone street of 19th century wooden rowhouses.

The rough and tumble president's childhood home displays the shirt he was once shot in and the speech that saved him.

Finally, you don't have to be a pious Swedish seaman to relax like one.

The famous author's cottage hideaway.

Once the tallest building in the world and the site of "the highest dinner ever held in New York" this building now holds the most expensive penthouse in the city.

The oldest surviving synagogue in New York City is now a soaring art space.