An ancient tunnel in Jerusalem built to redirect water in the event of a siege is one of history’s great architectural innovations.

Descend 2,030 years into the past in an ancient tunnel built to support Jerusalem's most famous wall.

This family tattoo parlor has been inking religious pilgrims in the Middle East for 700 years.

This "Jewish Sistine Chapel" was designed to reinvigorate Judaism's artistic legacy but was almost lost to misguided restoration.

This nightmarish children's plaything was left grotesque to help kids conquer their fear.

The remains of this ancient fortress atop a manmade hill look as though they were built into a volcano.

As the Dead Sea continues to deplete, massive sinkholes open along its banks.

This daunting 1st century fortress was purportedly the site of one of the most dramatic revolts of the Jewish-Roman wars.

A vast collection of rare books, manuscripts & extraordinary objects illustrating the history of medicine.

America's oldest Eastern European synagogue provided the immigrants of crowded Lower East Side tenements a space of sanctuary.

This was one of the first (and last) university-built and operated nuclear reactors.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

A hands-on traveling collection of the innovative devices of yesteryear.

A veritable variety of odds and ends.

This hidden library of physiological ephemera contains centuries worth of knowledge on the vim and viscera of the human body.

A Manhattan courthouse hides a small but scathing memorial to Holocaust injustice.

Three-story slide through the New Museum.

A masterpiece of LGBT art has been restored in what may now be the most valuable restroom in America.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

A living archive of urban activism and space reclaimed.

A clock set into the concrete outside a Manhattan jeweler has been telling time underfoot for over a century.

This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

The world's oldest hologram gallery and the labyrinthine laser laboratory of a holography pioneer.

Mysterious 500-year-old tapestries depict a unicorn hunt.