Golden Gate Park's historic collection of plants.

San Francisco's oldest surviving monument and meeting place for 1906 survivors.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.

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

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

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

Olfactory delights in San Francisco's Botanical Gardens.

A monument to the center of the North American continent may be off by a few miles.

Shoreline strewn with the remains of ghostly fallen trees.

A surreal landscape where fanged rocks rise from the ground and the ocean feels like a great mystery.

This "floating railway" is one of the world's oldest monorail systems.

The 1852 novel "Uncle Tom's Cabin" lends its name to a subway station, a street, and several shops on the edge of Berlin.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

The skeletal frame of a decommissioned gas-pumping station offers breathtaking views of greater Berlin.

Metro station with a claim to rock n' roll fame.

Cold war icon and onetime "hole" in the iron curtain.

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

Thousands of coffin-like pillars make up this controversial Holocaust memorial.