Seven mini rowhouses fill the gap between 54 and 70 Westerstraat.

A floating cat sanctuary on an Amsterdam canal.

One of seven Jewish catacombs in Rome and one of only two open to the public.

A collection of objects supposedly singed by the hands of souls in purgatory.

The underground sanctuary of a mysterious ancient cult.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

Architectureal fantasy quarter of Rome.

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

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."