Never actually a tree at all, this spot was the site of London's public hangings for nearly 600 years.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

A quiet memorial to those who died saving others in the heart of the City of London.

The barrel-made lookout from Shackleton's final ship is tucked away in the crypt of one of London's oldest churches.

This small collection of rare books was uniquely locked up for safe keeping.

Public access to clean drinking water was an instant hit among the masses.

A musical composition 1000 years in length plays at the Trinity Buoy Wharf in London.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

This beautiful Victorian ironwork masterpiece was built to keep London from smelling like poop.

A closed London rail station created to cart away the dead still bears the marks of attempts to make it less morbid.

A collection dedicated to the treatment of disease, held in London's oldest hospital.

The anatomical-pathological collection of a man who changed surgery.

A special shop catering to the needs of things that go bump in the night, and also helps kids become writers.

English antique dealers with a taste for the unusual.

A clock designed to run with perfect accuracy for 10,000 years.

Abstract dinosaur models in London.

A rare view of a preserved Victorian science museum.

Chicago's North Park Village was once the largest municipal sanatorium in the country.

Nonprofit art center that promotes outsider, intuitive, and self-taught art.

A speakeasy takes on Chicago's drinking culture.

This morbid, delightful curiosity shop offers everything from animal bones to human teeth.

The beloved home to all publications indie, erotic, and punky.

The Art Deco artwork depicts gilded carriers of deadly illnesses.

A collection of machines designed to break things for science.