He was the quintessential outlaw: Billy the Kid. This former cattle rustler became one of America’s first celebrity gangsters — that is, until he was gunned down at the tender age of 21. Who was Billy the Kid, and how did his infamous death on July 14, 1881, become such a hotbed of conspiracy theories? Head to the Wild West with donwildman when you stream Mysteries at the Museum’s “Who Killed Billy the Kid?” at the #linkinbio. 🤠🐴 #discoveryplus #matm #mysteriesatthemuseum 📸: Hulton Archive/Stringer via Getty