One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

The Tudor-style cottage in the middle of the square is not quite what it seems.

This ancient oak plays host to carvings of magical elves, gnomes, witches, and other creatures prominent in local folklore.

The pockmarks across the building's facade are remnants of the Blitz.

The rose garden in Regent's Park where Pongo and Perdita met for the first time in Disney's "101 Dalmatians."

This knockout museum lies in a sleepy corner of London.

A commemorative plaque at the door pays tribute to an "American Patriot" known for his betrayal.

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

These ornate arches show how the course of the River Thames has changed.

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

The medieval woodcut-style artwork chronicles life in medieval London.

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

A faded reminder of what was once a common sight in London during the Blitz.

The famous polar explorer stands outside the Royal Geographical Society's headquarters.

This picturesque horseshoe weir was first built in the 1600s to prevent flooding in the town of Bath.

Ancient human remains unearthed around the iconic monument.

Famously misunderstood wonder of the ancient world

A replica of the steam engine that hauled Queen Victoria's Royal Train is on display at Windsor.

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

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

Once designed as the entrance to Buckingham Palace, this structure was later relocated and stands as a victory arch.

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

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

An incarceration museum on the spot of possibly the oldest prison in England.