MADRID, Spain — More than 20,000 things people left on planes and at airports, including a wedding dress and a pair of rudimentary stilts, were auctioned off Tuesday as Madrid’s airport cleared out its lost-and-found department.

The items were divided up into nine lots, such as clothes and jewelry, and prospective buyers submitted bids over a one-week period that ended Monday. Most were merchants who run secondhand stores, said the national flagship carrier Iberia, which organized the sale.