An ordinary pond with fish from out of this world.

Once a black market electronics marketplace, now an otaku shopper's paradise.

This elaborate towering structure was once famed for its revolutionary height.

Yo, Adrian!

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

The 28-foot granite map plots the locations of 40 theaters in New York City.

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.

The original toys that inspired the beloved children's stories are on display at the New York Public Library.

The New York hotel where tragic visionary Nikola Tesla spent his final hours, destitute and alone but for the pigeons.

Cryptic messages embedded in the New York City sidewalk.

The "Seinfeld" diner.

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.

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

A model home in the Medical Examiner's Office in which grisly death scenes are staged to train forensic investigators.

The site where Poe "in great distress, and ... in need of immediate assistance" likely died.

This bug-eyed water wheel uses the power of the Sun to clean up Baltimore Harbor.

Baltimore's classic clock tower was once topped by a rotating, 20-ton medicine bottle.

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

Washington's iconic carousel has a nice piece of Civil Rights history.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

It was once the base for a series of domestic terror attacks.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.