The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

This museum offers an actual time machine back through Colorado's past.

A unique auditory experience right on the sidewalk.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

Look up from the busy streets to discover how time is kept!

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

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

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.

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

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

The 2,000-year-old beam is tucked within the pedestrian entrance to the old London Bridge.

Only a few pieces remain of the structure that carried people and goods across the Thames for some 600 years.

The commemorative stone column conceals a secret laboratory.

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

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

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

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.

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

The world's largest grapevine has produced a delicious harvest at Hampton Court Palace for almost 250 years.

In 2013, historians discovered a hidden room devoted to the art of making royals' hot chocolate.

England's oldest surviving hedge maze has been confusing visitors for over 300 years.