Tartessos (also Tartessus) was a harbor city on the south coast of Spain, at the mouth of the Guadalquivir. It probably existed already before 1000 BC, and its inhabitants were traders, who seem to have been the ones to discover the route to the Tin Islands (Britain or more precisely the Scilly Islands). Tin was a much-wanted product in those days, as it was necessary for the production of bronze, and the people from Tartessos became important trading partners of the Phoenicians, who nearby built a harbor of their own, Gades (current-day Cadiz). In the 6th century BC, Tartessos disappears rather suddenly from history. One theory is that the city had been destroyed by the Carthaginians who wanted to take over the Tartessans' trading routes.
In the Bible, Tartessos is known under the name of Tarshish. Although several finds have been made in southern Spain that are ascribed to the Tartessan culture, the city itself has not been recovered by archeologists.