An exceptional engineering feat that facilitates the migration of salmon upstream during their breeding season.

One of Scotland's earliest hydroelectric power stations.

Possibly the oldest living thing in Europe, more likely a pagan survivor.

The extra platform at Gloucester Road has been used for art displays for over 25 years.

An architectural oddity hides in plain sight on this iconic London bridge.

Hear the quietest sound from across the dome.

This coffee shop lies hidden beneath a historic church.

This monument is dedicated to a young boy who survived a disaster that forced Edinburgh to reevaluate its building codes.

This sculpture of disembodied body parts forms a poignant memory of the horrors of World War II.

This charming old building's loose connection with the Scottish Reformer is what saved it from demolition after it split apart.

The dance of this huge clock is a magnificent and eerie commentary on good and evil in the history of humankind.

This early version of the guillotine was used to execute the man responsible for its construction.

There are plenty of wonderful panoramic vistas in Edinburgh, but not many are hidden smack in the middle of the Old Town.

Erected in memory of Sir Arthur Conan Doyle, who was born close to this spot, this statue commemorates the author and his famous detective.

Brass bricks outline the locations of Edinburgh's lost, lively market stalls.

The world’s first museum dedicated to the history of childhood opened in Edinburgh in 1955.

This otherwise ordinary close on the Royal Mile constituted the end of the world for Edinburgh’s poorest residents.

A spring purported to have healing properties lies just outside Scotland's capital.

A park where you can watch the highway zoom past.

Ruins from the Parthenon and petrified wood line the interior of one of the world's most famous monuments.

Railroad officials in the early 1900s sought to spare travelers the sight of Roman soldiers’ private parts.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

The grand marble structure next to the White House is Andrew Carnegie's temple to Pan-American diplomacy.