From Wikipedia

H. H. Holmes

Herman Webster Mudgett
(May 16, 1861 – May 7, 1896)
better known under the alias of
Dr. Henry Howard Holmes,

was an American serial killer. Holmes opened a hotel in Chicago for the 1893 World's Fair, which he built himself and was the location of many of his murders. While he confessed to 27 murders, of which 9 were confirmed, his actual body count could be higher.

The case was notorious in its time and received wide publicity via a series of articles in William Randolph Hearst's newspapers. Interest in Holmes' crimes was revived in 2003 by Erik Larson's The Devil in the White City, a best-selling non-fiction book that juxtaposed an account of the planning and staging of the World's Fair with Holmes' story.