World's first "penitentiary," meant to be humane, drove men insane.

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

Elevated freight railway turned wildly successful urban park.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

The most confusing clock in New York.

This exemplar of modernist architecture is meant to captivate and inspire students of the Cooper Union.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

One of only two commuter aerial tramways in the United States.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

At 207 feet, one of the world's longest continuous escalators.

Largest Roman Catholic church in North America.

Giftshop catering to cryptozoologists and anyone with a sense of humor.

The privately owned cemetery that holds room for Washington's finest when they step down from life.

This 38-drawer structure claims the superlative title, but it isn't the world's only giant filing cabinet.

A massive sustainable farm designed by the mastermind behind Central Park.

This unusual building straddles two countries.

Lake Champlain Bridge, the recently demolished and rebuilt bridge where they filmed "What Lies Beneath".

The highest point in the state of New Hampshire, and while unlikely "the worst weather in the world," it sure seems that way to hikers.

A small chapel celebrating the spiritual bond between dogs and humans.

A New England curiosity cabinet, one hundred years on.