This mountain trail inspired Nietzsche to complete his magnum opus.

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

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

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

A huge musical instrument played by the ocean.

A beautiful multicolored mound formed by the mineral deposits of the Orenda Spring.

This Parisian café sticks almost exclusively to an ethos of reuse.

The narrowest street in Paris.