(Recreation of the city of Atlantis, which was speculated to be the city of Tartessos, and an imagining of a Turdetan warrior)
The Tartessic culture is the oldest one in the Iberian peninsula, dating from around the year 1000 BC to 550 BC. It spanned practically all of Western Andalucía, in the provinces of Huelva, Cádiz and Sevilla, with some dispersion to the southern parts of Extremadura. It was born due to the unique geographical and metallurgic properties of the area; it is known for the Riotinto mines, full of iron and other minerals, as well as other rich mining areas. Its geographical makeup has changed quite a bit, in Ancient times the Tartessic Gulf occupied most of this area, which later became the Ligustinus Lake in Roman times, and it's now a wetland area called Doñana. Here's the evolution of the area from Tartessic times through the Roman era to today:
It was a society led by autonomous chiefs dedicated mainly to agriculture, mining and fishing. They become richer due to the later influence of Phoenician and Punic peoples in Gadir and other nearby areas, integrating and living peacefully with them, mainly due to commerce. Some of the main Tartessic population centers were Cabezo de San Pedro (in Huelva), Onuba (modern Huelva), El Carambolo (in Camas, Sevilla) and Casas de Turuñuelo (in Guareña, Badajoz). El Carambolo is particularly noteworthy as here the Treasure of El Carambolo was found, a probably funerary dowry of golden pieces, mostly necklaces and bracelets.
There was a noteworthy amount of sanctuaries that controlled different economic areas, the most impressive one being the Cancho Roano sanctuary (near Zalamea de la Serena, Badajoz). Here's a recreation of it:
One of the main archaeological artifacts associated with Tartessos are the Southwestern Steles, divided in the Warrior Steles and Diademed Steles. There's no consensus in their function, but it is known they were directly pinned in the ground, and the most accepted theories say they could be funeral steles or territorial demarcations.
Finally, Tartessos appeared and received its name from Greek mythology. Hecateus talked in the 7th century BC about king Arganthonios of Tartessos, who ruled the land for more than 100 years and was the wisest of men. Tartessos also appeared in one of the Twelve Labours of Hercules, in which he had to steal Geryon's cattle. In some versions of the myth, Geryon was a giant and king of Tartessos. Finally, the Tartessic kings Habis and his father Gargoris were immortalized in Epitome by Justin.
Their demise coincided with the depletion of the superficial levels of the mines, and they evolved into the Turdetani, a non-Iberian people specialized in salted fish, fish curing and fishery in general, starting an industry that was vital during the Roman Empire, as that same area was later used to produce the famous garum. Turdetani survived until Romanization happened, and most Baetic cultural aspects derived from them. They had a different writing system to the Iberians, and were very influenced by Eastern cultures. Its largest known settlement was Tejada la Vieja (near Escacena del Campo, Huelva).