The chapter discusses the broad use of Wargaming. It will start by describing the role of Board War Gaming in military environments, considering the effect it had on historical events, such as how the US Navy inter-war wargaming underpinned the eventual success against the Japanese Empire, in World War II. The subject will be further developed by describing how Wargaming is exploited nowadays, featuring Locked Shields: the world’s largest and most advanced international technical live-fire cyber defense exercise organized by NATO, as use case, and analyzing Capture the flag (CTF) contests overall along with cyber ranges. The focus will be on the importance that such competitions have in today’s world: gaining awareness of security flaws through “battles”, specialized training, and the fact that it constitutes a new approach to learning, totally hands-on.