An artsy hidden staircase leads to breathtaking views of San Francisco.

Largest Roman Catholic church in North America.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

This London plaque marks the spot where David Bowie's famous alien made his debut.

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

The signs of a long buried road can still be found hidden beneath a London sewer grate.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

Orthodox church partially financed by Tsar Nicolas II.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

Once called the "Polish Gold Coast" it is an icon of the neighborhood that bears its same name.

The unluckiest U-boat in the entire German fleet is now on display in a Chicago museum.

A hot dog stand where the heads are just as hot as the dogs.

These pretty kitties killed and ate as many as 135 railway workers.

A display of magnificent stained glass windows is the first exhibit of its kind.

The 606 is a decade in the making.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

A century-old hotspot for jazz, frequented by everyone from Charlie Chaplin to Al Capone.

This $3 million model train takes you through Chicago, Seattle, and the thousands of miles in between.

Chicago's largest cemetery is full of beautiful Victorian monuments and more than a few ghost stories.

Cemetery featuring rare glass-fronted columbarium.

This historic hotel invented the chocolate brownie.

All of Chicago's wood-paved streets are long gone but two alleys remain.

Each of these gorgeous, intricately decorated rooms is painstakingly crafted to the scale of 1 inch: 1 foot.

What's left of the ruins of the 1893 Columbian Exhibition, or World's Fair, also known as the White City.