Steve Ditko, the visionary illustrator who co-created Marvel’s Spider-Man and Doctor Strange, has died at age 90. While the New York Police Department did not elaborate on his cause of death, they confirmed Ditko was found dead in his apartment on June 29. Police believe he died two days earlier. Ditko worked closely with longtime Marvel editor-in-chief Stan Lee to create iconic characters now featured in hit movies before leaving falling out with Lee and leaving Marvel. Ditko's other characters — often in self-published books later in his career — include The Question, Squirrel Girl, and Mr. A.