Minecraft is a sandbox construction game, inspired by Infiniminer, Dwarf Fortress and Dungeon Keeper, created by Markus Persson, the founder of Mojang AB. The game involves players placing and breaking various types of blocks in a three-dimensional environment. The player takes on an avatar that can break and place blocks, forming fantastic structures, creations, and artwork, on multiplayer servers and singleplayer worlds across multiple game modes. Minecraft is available to all players for €19.95 (US$26.95, £17.95). Singleplayer and multiplayer, when purchased, can be played in the user's web browser, or using the downloadable launcher. Minecraft Classic is available to play for free. Minecraft development started around May 10, 2009, and pre-orders for the full game started being accepted on June 13, 2009. Minecraft's official release date was November 18, 2011. On April 5, 2013, Minecraft for the computer reached 10 million sales.