Ingenio Boca de Nigua is a historic colonial sugar mill in the Dominican Republic, originally constructed in the 16th century and rebuilt in the 18th century as part of the early American sugar industry. This tentative UNESCO World Heritage site features well-preserved ruins of industrial structures, including a horse-powered trapiche (cane-crushing mill), boiler house, vaulted oven areas, and organized warehouses around a central patio, built with brick and stone masonry.