Wander too far away from the World’s Columbian Exposition of 1893 and you might disappear forever.

Herman Mudgett, an enterprising serial killer, built a row of three-story buildings near the Chicago fair and opened it as a hotel. Guests discovered — too late — that it was a maze of more than 100 windowless rooms, where Mudgett would trap them, torture them in a soundproof chamber, and then asphyxiate them with a custom-fitted gas line.

Then he’d send the bodies by chute to the basement, where he’d cremate them or sell them to a medical school.

This went on for three years, until a fire broke out and police and firemen discovered the trap. No one knows how many people Mudgett killed; he confessed to 27, but estimates go as high as 230.

He was hanged in Philadelphia in 1896.