A tribute to the pop culture icon overlooks this Washington D.C. intersection.

A celebrity from the late Cretaceous period.

The iconic D.C. restaurant where the Cuban Missile Crisis was negotiated, now a Walgreens.

FDR's Art Deco hospital tower was hopelessly inefficient.

There's a crumbling old mansion inside the Smithsonian National Zoo.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

A much-maligned monument to teetotalism.

Artists and musicians now rule over this former rail station.

Lovers proclaim their unbreakable bond by leaving their names on locks fastened onto the Shoreditch fence in East London.

A computer bug so primitive it was an actual insect.

Dedicated to the art and science of glass in equal measure, this space is as much laboratory as museum.

The 20th-century chapel’s intricate woodwork includes amazing details, most notably angels playing bagpipes.

This 16th-century house tells the city's history through old artifacts and quirky tales.

This extinct volcano rises above Edinburgh and is special for its panoramic views over the city.

The remains of the great moral philosopher reside in a university in London.

Drink your espresso at a Victorian-era urinal in this underground-restroom-turned-coffee-bar.

A glorious pub known for a spiteful printing feud and its famous typeface lost—then found—at the bottom of the Thames.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

A makeshift shrine to the late rock star is still kept up on the nondescript façade outside 1 Logan Place.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

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

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

This 16th-century close preserves an unusual piece of Edinburgh's transportation history.

Touching this 18th-century Scottish philosopher’s toe allegedly conjures good fortune.