The world's first indigenous rooftop farm boasts 2,000 plants from more than 35 different native Australian species.

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

This Underground station has been a popular filming location for decades, even before it closed.

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

The handiwork of a underdog clockmaker who solved an impossible problem for an Empire, and forever revolutionized seafaring.

This pump on the bad side of Victorian London betrayed a horrifying revelation about the water supply.

A memorial to a dog that inspired rioting in the streets of London.

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

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

The television series' iconic giant foot was borrowed from this classical painting.

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

Scattered throughout London are ancient remnants of the city's former bounding wall.

The signs of a long buried road can still be found hidden beneath a London sewer grate.

The site of London's first coffee house has been serving refreshments of one kind or another for 360 years.

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

This alley off Edinburgh's Royal Mile contains remnants of the city's seedier history.

A labyrinthine network of chambers with a storied past hides below Edinburgh's South Bridge.

There was a top secret plan during World War II to seal a group of soldiers inside the rock.

Single runway interrupted by a busy road that cuts across its middle.

The largest oak in England is said to have been the hideout of Robin Hood and his Merry Men.

A historic observatory precariously perched at the "Top of Europe."

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

An 11th-century runestone decorates the halls of Terminal 2 of this Scandinavian travel hub.

The library's graceful rotunda is like a bibliophile's temple.