London's smallest police station is barely the size of a phone booth.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

This coffee shop lies hidden beneath a historic church.

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

Ship-sized kinetic sculptural fantasy.

This restaurant's specialty is "a major enigma for food historians."

A mysterious pair of mice eating a piece of cheese is London's smallest public sculpture.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

A Roman spa buried deep beneath the City of London.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

The Great Fire of London and the regulation of one-way streets both started in this alley.

The commemorative stone column conceals a secret laboratory.

This legendary stone is of unknown origin, and throughout history has been a literal touchstone for British leaders.

Rebuilt remains of a temple to Roman god Mithras.

The oldest farmer's market in America is so ancient it was approved by the King of England.

One of the world's oldest continually operating bookstores.

The site where Poe “in great distress, and ... in need of immediate assistance” likely died.

This Asian-inspired tower in a lush urban park provides spectacular panoramic views of Baltimore.

This beautiful vintage movie palace has seen little change in form or function since the 1920s.

A genuine Tudor manor transported piece by piece from England.

Inspired by a foil-wrapped potato, (seriously) the Markel Building has been deemed one of the 10 ugliest buildings in the world.

This equestrian statue of Constantine the Great has been the subject of criticism for centuries.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.