The popularly known Estufas del Retiro or Retiro Stoves are a series of nineteen greenhouses; some old that were scattered throughout the park, others from historic Madrid gardens, such as the Duke and Duchess of Alba’s Palace of Liria, and others of modern construction. The area where they are located, known as the Vivero de las Estufas or the Stove Nursery, is almost four hectares in size and, in addition to the greenhouses and areas for growing ornamental plants, houses a collection of traditional gardening tools, implements and instruments that allow us to better understand the work of gardeners and their historical development. It also has an area used for urban allotments where the citizens of Madrid grow their own fruit and vegetables. Since 1890, the nurseries have occupied a large area near the Fallen Angel and can be visited by appointment with the Retiro Environmental Information and Education Centre.