An essential stop before plundering, BYO Cutlass.

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

A winding path built in secret on the edge of the continent.

A huge musical instrument played by the ocean.

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

The loneliest island in New York.

Surreal riveted sea forts once protected the Kent shores from German attack.

A gargantuan crystal kingdom.

Thousands of exquisitely carved stone water storage wells, hundreds of stone steps fill this exquisite medieval stepwell.

World's first "penitentiary," meant to be humane, drove men insane.

Museum on French naval history, with magnificent figureheads, a historic diving suit, and a boat used by Napoleon.