Solitaire, also known as Klondike, is a single-player card game that has been a staple of computer gaming since Microsoft included it with Windows 3.0 in 1990. The game uses a standard 52-card deck and challenges players to sort all cards into four foundation piles by suit in ascending order (from Ace to King). To achieve this, players must strategically move cards around the tableau, building descending sequences alternating between red and black cards. Solitaire combines elements of luck and strategy, making each game unique. It's known for being both relaxing and mentally stimulating, offering a perfect balance of challenge and accessibility.