This wondrous guide for the curious and the intrepid takes readers on a lyrically written tour of eighteen of the world’s most captivating architectural mysteries. Delve into both the secretive places themselves and the eccentric and obsessive minds that created them. Visit a chamber of skulls high in the Swiss Alps, a Japanese temple full of traps, a Parisian apartment locked and untouched since World War II, a Prohibition-era speakeasy in Washington, DC, and a spooky “initiation” well in Portugal built by a secret society. How far down can you climb before losing your nerve?