At which 2014 Blizzard event was Overwatch formally unveiled?

Overwatch was formally unveiled at BlizzCon 2014. Blizzard announced the new team-based first-person shooter on November 7, 2014, during its annual convention.

The reveal followed the cancellation of Titan, Blizzard’s planned massively multiplayer online game. Parts of the Titan development team redirected their ideas toward a more focused hero-based shooter, eventually creating Overwatch’s colorful science-fiction setting and roster of distinct characters.

At BlizzCon, Blizzard showed a cinematic trailer, extended gameplay footage, and a playable demo. Fourteen characters were available to attendees, giving the public an early look at the game’s cooperative objective-based combat and sharply differentiated heroes.

The announcement date is easy to mix up with later milestones. Overwatch entered closed beta in October 2015, held an open beta in May 2016, and launched commercially on May 24, 2016. BlizzCon was the unveiling event, not the release date or beta launch.