The crown jewel of the Queens Museum is a nearly 10,000-square-foot architectural model of the city originally built for the 1964 World's Fair.

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

One of the last few places in Manhattan that employed a pneumatic systemic keeps it on display.

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

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

The fanciest public restroom in New York City boasts fresh flowers, art, and a classical music soundtrack.

Mysterious 500-year-old tapestries depict a unicorn hunt.

This sculpture pays homage to the street sweepers of Madrid since its inauguration in 2001 in Plaza Jacinto Benavente.

This 40-meter waterfall of light graces one of the most iconic stations in the Madrid metro network.

At this century-old barbershop, clients used to be entertained with a glass of brandy and a cigar.

In this 400-year-old hotel in Madrid, you'll find a comb in every room, an old clock, and maybe a ghost.

Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

Order cookies baked by cloistered nuns in a 400-year-old monastery.

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

The only urban monument in the world designed by the great surrealist painter Salvador Dalí.

Commonly acknowledged as the only public monument to the Devil himself.

This open-air sculpture museum is located under a bridge in the center of Madrid.

The oldest building in Madrid.

One of the best examples of the modernist movement in Madrid.

Meant to resemble a massive tree, the building is the best example of Spanish organicist architecture in Madrid.

King Carlos IV laid the first stone during construction of this chapel.

Inaugurated three times, this tower offers some of the best views of Madrid.

Once a resting spot for King Fernando VII.

One of Madrid's oldest trees, with a long and colorful history, resides in El Retiro Park.