The International 2014 already had the largest prize pool ever seen in e-sports, but now it can boast one of the largest audiences too. The Dota 2 tournament, the fourth such annual event organized by the game's developer, Valve, was watched live online by more than 20 million people. At its highest, the number of people watching at the same time was over 2 million, a figure that Valve says doubled last year's peak concurrent viewership.

The viewer tally isn't the biggest in e-sports history — last year more than 32 million people watched the finals of Riot Games' League of Legends 2013 Championship Series — but Valve's $10 million prize pool easily outstrips the kind of money thrown around by Dota 2's pro-gaming rivals. The tournament also hit another important milestone for worldwide e-sports legitimacy — its final rounds were broadcast on mainstream US sports TV network ESPN, as well as on China's state broadcaster CCTV and European media network MTG Europe. Valve says the viewer total doesn't include those who watched the tournament on TV, tallying only the people who saw the action unfold online, either through streaming services such as Twitch or by using Dota 2's in-game spectator option.