The largest of London's subterranean rivers and once a mad, bad center of London life.

The bridge is a secret gallery of discarded gum that has been transformed into miniature masterpieces.

The last remaining example of the boatmen's perches that once dotted the south bank of the Thames.

Murals of the wild parties once held on the frozen River Thames.

The ground on which Shakespeare’s initial playhouse once stood.

This hand-painted advertisement is a literal sign of encouragement, however unintentional.

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

The ruins of a once-mighty medieval palace are hidden away in otherwise modern London

This one has sailed five times as far as Sir Francis Drake's famous ship.

In this cobwebbed old operating theater, you can practically hear the screams of the unanesthetized patients.

A sculpture outside London's oldest cathedral honors the Mohegan chief who died while petitioning the king.

This unassuming alcove in London’s famous Tower Bridge once served to capture, store, and display dead bodies from the River Thames.

There's an exclusive Beefeaters pub hidden in the Tower of London.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Graffiti from the 16th and 17th centuries cover the walls of this part of the Tower of London.

A mysterious suspended hand greets unsuspecting visitors at the Tower of London.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

The ritual has been performed uninterrupted for nearly 700 years.

These wire animal sculptures commemorate the exotic inhabitants that once called the Tower of London home.

A memorial for public executions that dates back to the 14th century.

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

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.