This hidden oasis features a stunning view of the Hudson River and the Palisades from a castle-like museum.

This translucent sculpture represents a quintessential component of New York City's skyline.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

The last living thing to come out of the rubble after 9/11 is now a symbol of hope and resilience.

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.

A strangely angled West Village home is the only monument to an explosion that took the lives of three American revolutionaries.

The notorious headquarters of a corrupt political machine.

The one-time office of the architectural firm that ushered in the Gilded Age is now a Club Monaco.

This monument to a veteran of the Mexican-American War is one of only two in Manhattan that serve as an actual mausoleum.

The former home of the reclusive "Weird Wendels" who dominated New York real estate a century before Donald Trump.

Tucked away amidst some of the most famous addresses in the world is New York’s only fraction of a street.

This huge work of functional public art replaced a landfill in New Jersey's Meadowlands.

The original shop where the iconic Belgian praline was invented.

This 12th-century castle majestically overlooks the city and the beautiful Mosel River valley.

The start of the group that straightened the teeth of a nation.

A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.

Home to the first child born to English colonists in North America, this colony mysteriously disappeared while waiting for supplies.

An awe-inspiring mosque in Morocco with one of the tallest minarets in the world.

The oldest monument in Marrakesh and the city's only surviving example of Almoravid architecture.

The largest madrasa in Morocco once housed more than 900 students within its exquisite walls.

It took 40 years to build this Eden-like garden in Marrakech, later restored by Yves Saint-Laurent.

One of the two original gateways into the Kasbah, this gateway is a nesting site for storks.

Deliberately hidden for centuries, the magnificent Saadian Tombs were eventually uncovered in 1917.

This vast masterpiece of Moroccan architecture spreads across 20 acres.