An auction is a public sale where items are sold to the highest bidder. Participants place bids, which are offers to pay a certain amount for an item. The auctioneer, who manages the sale, announces the starting price and encourages bidding until no one is willing to bid higher. Auctions can involve various items, including art, antiques, real estate, and collectibles. They can be held in person or online, allowing a wider audience to participate. Famous auction houses like Sotheby's and Christie's are known for selling valuable items to collectors and investors.