A discreet little stairway on St. Nicholas Avenue leads to a quaint and unexpected cobblestone street of 19th century wooden rowhouses.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

The astonishing collection of an infamous criminologist.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

Hidden away in a modern library are the remains of one of the 18th century's most celebrated wunderkammers.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

Behind the pink curtain, Au Bonheur du Jour, an art gallery of erotic archives.