Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

In Florence's great Duomo, a 26 foot fresco honors a mercenary famous for attacking Florence.

A slightly creepy gallery of plaster cast models in the same museum as Michelangelo's David.

Secret refuge and museum of the Duke of Florence.

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

This hydrochronometer was invented by a Dominican monk and is a prime feature in this garden.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

This subterranean oyster house has been the pearl of Grand Central Station since 1913.

Sniff the Titan Arum's rotting flesh.

An eerie diorama that captures the majestic nature of a few prehistoric-looking beasts.

Creating this diorama spurred naturalist Carl Akeley to begin advocating to protect the apes.

The history of the tea trade is told in bas-relief on this historic pair of Boston doors.

The site of Paul Revere's historic two lantern warning.

Where condemned pirates met their grisly end at the gallows on the River Thames.

The world's largest outdoor organ is played weekly by one of just two civic organists in the U.S.

This old-fashioned candy shop, ice cream parlor, and diner served as the setting for one of TV's most controversial series finales.

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

The sumptuous ceiling was one of the last things Charles I saw before his execution.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

The fierce beast perches atop a pedestal marking where the historic City of London gates once stood.

This marine reptile was discovered by one of the 19th century's greatest fossil hunters.

This plot of old-growth forest is the largest surviving remnant of New York City's original woodland.