A hidden three-foot-wide house separates these two regal churches.

A historic observatory precariously perched at the "Top of Europe."

It took over 100 years to decode this enigmatic epitaph for two buried brides.

The best way to get a sneak peek at the movies.

Colloquially known as "the lynching memorial," this is the United States' first memorial to the victims of racial terror at home.

Lehigh Valley barge No. 79 still gets tugged along - but now it houses a museum and unusual performances.

A strip of modern stores in historic buildings.

Four cars from the old system were once on display, but were removed in 2014.

An underground city of salt.

The humble fort that saved Washington.

Take in a rare, face-to-face glimpse of Lady Liberty at this tucked away Red Hook park.

A drawbridge named for a potentially intersex Polish national who fought alongside George Washington during the American Revolution, and an example of "Pulaski Red".

Nature and beauty amidst pollution and industrial wreckage.

The highest rapid transit station in the world.

The mass grave of a heroic Revolutionary War regiment sits below an empty lot near the Gowanus Canal.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

Although built to generate electricity for Marylanders, this dam has become an all-you-can-eat buffet for American bald eagles.

The medieval woodcut-style artwork chronicles life in medieval London.

An agreement meant to honor the Duke of Buckingham led to this unusually-named passageway near Charing Cross.

This beautiful Brooklyn monument over a crypt memorializes a grim and largely unknown story from the American Revolution.

The highest bridge in America was built for an almost unnervingly small amount of money.

A whale of a public art display towers atop Juneau's cruise ship dock.

Known as the “Official Greeter of Juneau,” this dog still welcomes ships and their passengers to Alaska.

Often mistaken for an office building, inside this venue is an amazing collection of Native Alaskan art.