In 1927, an English firm -Islas del Guadalquivir S.A.- purchased a significant extension of land, including 25,000 hectares from the Marquis of Casa Riera, to dewater and sanitise the swamps and marshes of the River Guadalquivir islands to encourage intensive rice production. Although this project eventually failed for economic reasons, it was the first serious attempt at intensive rice cultivation in this environment.
This firm built small hamlets (Dora or Colinas, Rincón de los Lirios, Alfonso XIII, El Puntal, Veta de la Palma and Reina Victoria) and numerous houses and outbuildings throughout Isla Mayor to house the first rice farmers.
The houses have a rectangular plan and an oval-shaped ceiling. These houses have ethnological, cultural and historical value as they provide insight into the conditions and way of life of the first settlers and inhabitants of the rice-growing area of the Guadalquivir Marshes.
They are currently scattered throughout the municipality.
They are scattered throughout the municipality and cannot be pinpointed on a map.