New York City's smallest piece of private property.

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

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

Tucked in the back of this amazing antique store is an important piece of medical history.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

Ancient serpentine sacrifice holder that has stood the test of time.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

Guatemalan womanizer, venerated during Holy Week.

An elaborate shrine dedicated to the four corners of the world unfortunately misses its mark.

This blowhole is supposedly caused by a trapped monster.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

The American Revolution was galvanized into serious action due to the tragic clash with British soldiers that occurred at this location.

This landmark cemetery in Boston was created more than 300 years ago.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

The most visited, and possibly most controversial, museum in Germany.

Macabre astrological automaton clock dating to the late 1400s.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

The Habsburgs' royal collections of art and wonders.