One of the most significant projects that Sundance Kid was involved in was the infamous Union Pacific train robbery in 1899, where he and Butch Cassidy successfully executed a heist that garnered international attention. This audacious act not only increased their notoriety but also demonstrated their strategic planning and execution skills. Sundance Kid, along with Butch Cassidy, masterminded several other high-profile robberies that secured their place as the most wanted outlaws of their time.