History of the world
Whether in prehistoric or historic times, people always needed to be near reliable sources of potable water. Settlements developed on river banks as early as 3000 BCE in Mesopotamia, on the banks of Egypt's Nile River, in the Indus River valley, and along China's rivers. As farming developed, grain agriculture became more sophisticated and prompted a division of labour to store food between growing seasons. Labour divisions led to the rise of a leisured upper class and the development of cities, which provided the foundation for civilization. The growing complexity of human societies necessitated systems of accounting and writing.
Andalusia
Several theories postulate that the first hominids in Europe were in Andalusia, having passed across the Strait of Gibraltar; the earliest known paintings of humanity have been found in the Caves of Nerja, Málaga. The first settlers, based on artifacts from the archaeological sites at Los Millares, El Argar, and Tartessos, were clearly influenced by cultures of the Eastern Mediterranean who arrived on the Andalusian coast. Andalusia then went through a period of protohistory, when the region did not have a written language of its own, but its existence was known to and documented by literate cultures, principally the Phoenicians and Ancient Greeks, wide historical moment in which Cádiz was founded, regarded by many as the oldest city still standing in Western Europe; another city among the oldest is the andalusian Málaga. During the second millennium BCE, the kingdom of Tartessos developed in Andalusia.