Looking strangely like Rome's Colosseum, this unfinished tower has dominated the skyline for over 100 years.

Yo, Adrian!

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

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.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Try not to get slimed in Tribeca.

Elevated freight railway turned wildly successful urban park.

Pop culture has helped to keep this iconic British building from being destroyed.

London's smallest police station is barely the size of a phone booth.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

A war-torn Olympic relic is being overtaken by graffiti and nature.