Justice League Unlimited pemiered 15 years ago today, and the world hasn’t been the same since.

The first episode, “Initiation” show the League finally convince Green Arrow to join their ranks.

The League expands their operations, enlisting new recruits from across the globe. The newest of these is Green Arrow, who has repeatedly refused to join the League. He is teleported to the rebuilt Watchtower. Opting against joining, he hitches a ride back to Earth with the team of Green Lantern, Captain Atom and Supergirl, who have been sent on a mission to stop a giant, uncontrolled, nuclear-powered defense robot in an unnamed Asian country existing in self-imposed international isolation.

Note: This episode also features cameos from over 30 other heroes, many of whom would be featured in subsequent episodes. Most notably, Green Arrow's decision to join the League is shown to be influenced by catching his first glimpse of Black Canary.