Klondike Solitaire is the most popular solitaire card game in the world. It gained fame when Microsoft released their version of Solitaire that came with the Windows Operating System. Most people think of Klondike Solitaire when they think of a solitaire game. In Klondike Solitaire, the player attempts to sort a 52 card deck by suit and in order into four piles of cards known as foundations. Cards can be moved between the columns, or to the foundations. The cards in the columns must be built down (from King to Ace) alternating color. When the player gets stuck he can click on the deck in the top left of the game screen.