Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

This theater opened in 1998, but both the building and the puppeteers who perform there have a distinguished history.

Outstanding taxidermy dioramas showcase the grandeur of the continent's wildlife with spooky realism.

A playground the size of a city block is a modernist monument to civic values and public housing.

A Victorian cemetery in the heart of Brooklyn remains a popular mecca of morbid curiosity.

One of only two remaining Victorian-era greenhouses in New York.

Final resting place of the immigrant who brought artificial seltzer water to America.

A curious friendship between two inanimate ladies.

A mass grave for victims of one of the city’s worst fires.

This metal eagle one of the final remnants of a newspaper that wanted to keep Brooklyn to Brooklyn.

This striking arch, one of the first architectural elements constructed in Prospect Park, was recently restored to its original glory.

This secluded ruin was once a home for exotic plants.

A tree that grows parallel to the ground was declared Brooklyn's "crowning curio" by the poet who saved it.

19th century cemetery hidden in Brooklyn's Prospect Park.

This elaborate tunnel is the first structure composed of cast concrete in the United States.

This ancient Egyptian obelisk still bears the wounds of World War I.

These wire animal sculptures commemorate the exotic inhabitants that once called the Tower of London home.

Its collection includes a broad array of social, geographic, graphic design, and political history.

The commemorative stone column conceals a secret laboratory.

Spitalfields' regal market goat is said to be a monument to the area's migrant population but most are pretty sure it's just a goat.

The majority of the museum's large collection is held in a storage space open to the public a few times a year.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

Dictionary Johnson’s favorite feline.