In the middle of downtown Brooklyn lies a 165 year old secret hidden right below the surface (closed to the public indefinitely).

Detailed facade of a brownstone in Boerum Hill.

This once-private estate is now a dreamy, meditative garden that's open to the public.

The only intersection in America where the buildings on all four corners were built pre-Revolutionary War.

The world's largest kaleidoscope, designed by a 1960s psychedelic artist.

The only quarter of the Old City not dedicated to a major world religion.

This historic rec center in the heart of Israel is a bastion of peace and togetherness.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Traveling collection of amazing automata.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

America's most famous piece of self-built architecture.

A snapshot of the city's fascinating voodoo culture.

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

The legendary building that needed ghostly approval before being built.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

Canyon walls shrouded in ferns.

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

This massive redwood tree has a hole in the base big enough to drive through.

A trash dump made beautiful by nature's power.

Over a thousand feet beneath the Detroit streets is a subterranean metropolis few are allowed to enter.

These enduring murals depicting a distinctly Marxist tribute to capitalism could not even be defeated by McCarthyism.

This sprawling bookstore spans four floors and has more than a million books in stock.

One man's attempt to create an artistic wonder on a run-down block in Detroit.

The Beaux-Arts aquarium boasts a vast collection of saltwater and freshwater fish on an island in the Detroit River.