"We’re starting with ESL One Frankfurt 2015 in June this year, where the prize money has been raised from US$150,000 to US$250,000 - and this is just the beginning," Ulrich Schulze, ESL's managing director of pro gaming, said in a statement. "ESL One is here to set a new standard for professional Dota 2 events at this level. We’re dedicated to pushing the boundaries, and giving players from around the world more chances to make their careers as professional gamers is a key aspect of that."
As MCV UK pointed out, last year's Dota 2 series consisted of two events, in Frankfurt and New York. Assuming my math is correct, 2015 will see that number at least double, with tournaments set to take place "in some of the world's most iconic stadiums and arenas."
The news follows closely behind last week's announcement that the ESL will hold the world's largest Counter-Strike: Global Offensive tournament in Cologne, Germany, with its own $250,000 prize pool funded entirely by the ESL. I'd say it sounds like things are going pretty well over there.