League of Legends is a multiplayer online battle arena video game developed and published by Riot Games for Microsoft Windows and Mac OS X, inspired by the mod Defense of the Ancients for the video game Warcraft III: The Frozen Throne. It is a free-to-play game, supported by micro-transactions. The game was first announced on October 7, 2008, and released on October 27, 2009. League of Legends was generally well received at release, and has grown in popularity in the years since. According to a 2012 Forbes article, League of Legends was the most played PC game in North America and Europe in terms of the number of hours played. As of January 2014, over 67 million people play League of Legends per month, 27 million per day, and over 7.5 million concurrently during peak hours.