H.H. Holmes, born Herman Webster Mudgett in 1861, is often considered America's first serial killer. He gained notoriety during the 1893 World's Columbian Exposition in Chicago, where he built a hotel designed with hidden rooms, trapdoors, and soundproof walls. This structure, often referred to as the "Murder Castle," was the site of numerous alleged murders. Holmes lured victims, primarily young women, to his hotel with promises of employment or shelter. After their disappearance, he would often collect insurance money on their lives. He was arrested in 1894 and later executed in 1896, leaving behind a legacy of horror and intrigue.