Polymarket is a decentralized prediction market platform that allows users to bet on the outcomes of various events, such as elections, sports, and other significant occurrences. It operates on the Ethereum blockchain, enabling users to trade shares in the outcomes of these events using cryptocurrency. Users can create and participate in markets, with the potential to earn profits based on their predictions. The platform aims to harness the collective knowledge of its users, making it a unique tool for gauging public sentiment and forecasting future events.