Parque Nacional de Doñana
This national park, one of the largest in Europe, occupies marshland at the mouth of the Guadalquivir river. It has a fragile ecosystem and is an ideal refuge for migratory birds. The park comprises three different areas: the salt marshes (marismas), with their very high salinity; the sand dunes, which advance inland at a rate of 6m a year; and the cotos, covered in scrub. These incredible landscapes can only be explored by 4x4 from the El Acebuche visitors' centre.