An impromptu shrine appeared shortly after beloved "Torchwood" character Ianto Jones was killed off the show.

The castle still holds traces of the abandoned Roman fort it was built atop.

The only Roman honorific column in Istanbul.

The legendary luxury train passage is commemorated with a charming museum inside its former eastern terminus.

A gorgeous, Gaudí-esque stairway constructed in the city of Istanbul by a prominent Jewish family.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

A marvel of Byzantine engineering under the streets of Istanbul.

These 19th-century gas tanks were remade into an apartment complex.

The world’s second-largest flood defense barrier has protected London for decades.

London’s first road overpass is so old that it was originally built for horse-drawn carriages.

This tribute to the fictional detective stands at the famous literary character's address.

For more than half a century, an enormous feline has watched over this London neighborhood.

Chelsea's soldiers were given strict orders when crossing this historic bridge.

A small stone monument marks the spot on Stavely Road where the first of hundreds of missiles touched down during World War II.

Once designed as the entrance to Buckingham Palace, this structure was later relocated and stands as a victory arch.

This black cat was actually designed to ward off bad luck.

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

A monolithic monument in Greater London.

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

A museum that chronicles the interesting and often dark history of the London docklands, once one of the major trading ports of the world.

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

At the top of the hour, figures of the London department store's two co-founders emerge and bow to each other.