Eighty million natural history specimens call this gargantuan museum home.

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

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

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

This legendary stone is of unknown origin, and throughout history has been a literal touchstone for British leaders.

A quiet memorial to those who died saving others in the heart of the City of London.

Hear the quietest sound from across the dome.

An unusual round church in London with a Templar past.

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

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

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

The century-old bell and clock tower at UC Berkeley is the third-tallest in the world, and has fossils.

After serving in World War II and picking up Apollo astronauts, this aircraft carrier has been turned into a museum overlooking the San Francisco Bay.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Golden Gate Park's historic collection of plants.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

Now housed in a museum, this giant pink elephant stood in downtown Seattle for more than 60 years.

A walk through the historic city center, under the streets of Seattle.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

A former waterfront market is now in the center of town due to some interesting Boston engineering.

Look closely and you’ll notice that the color changes a third of the way up the tower.