The "Seinfeld" diner.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

This subtle Berkeley paving stone actually marks off a lawless tube of air that extends into space.

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

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

A century and a half of research in the sciences and natural history, still going strong.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

San Francisco's newly reopened hands-on science museum.

A historic hotel that made a cameo in Hitchcock's classic film has no intention of letting guests forget its fame.

Visit a surreal landscape so otherworldly NASA actually used it to train the Apollo 17 crew.

This futuristic German television spire is actually the world's largest digital clock.

Tiny castle in the middle of the Rhine made you pay to pass.

The Bauhaus-style former industrial complex is considered the world's most beautiful coal mine.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

The fairy tale castle of the “fairy-tale king,” this was also the inspiration for Disney’s “Sleeping Beauty.”

As one of the world's largest hydroelectric dams this plant took two countries to get built.

An art museum with an eclectic design and a scandalous past.

One hundred years ago this small house in downtown Zürich became the birthplace of the Dada movement.

Vines grow up the metal bars in this public park created from an old machine factory.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

Go inside to really appreciate this 500-year-old technological masterpiece.

Possibly the oldest church in Barcelona, this basilica has its pagan and Christian mythologies all mixed up.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.