from the Neolithic period have been found in Gibraltar's caves, mostly of types typical of the Almerian culture found elsewhere in Andalusia, especially around the town of Almería, from which it takes its name. There is little evidence of habitation in the Bronze Age, when people had largely abandoned the tradition of living in caves. During ancient times, Gibraltar was regarded by the peoples of the Mediterranean as a place of religious and symbolic importance. The Phoenicians were present for several centuries, apparently using Gorham's Cave as a shrine to the genius loci of the place, as did the Carthaginians and Romans after them. Excavations in the cave have shown that pottery, jewellery and Egyptian scarabs were left as offerings to the gods, probably in the hope of securing safe passage through the dangerous waters of the Strait of Gibraltar. The Rock was revered by the Greeks and Romans as one of the two Pillars of Hercules, created by the demigod during his tenth labour when he smashed through a mountain separating the Atlantic and the Mediterranean. According to a Phocaean Greek traveller who visited in the sixth century BC, there were temples and altars to Hercules on the Rock where passing travellers made sacrifices. The Spanish later symbolised the importance of the Pillars of Hercules with a heraldic device consisting of a pair of columns with a scroll wrapped around them – a symbol that became the $ sign and the related Portuguese cifrão (). To the Ancient Romans, Gibraltar was known as Mons Calpe, a name perhaps derived from the Phoenician word kalph, "hollowed out", presumably in reference to the many limestone caves in the Rock. It was well known to ancient geographers, but there is no known archaeological evidence of permanent settlements from the ancient period. According to the Roman writer Avienius, the ancient Greek traveller Euctemon recorded that There were more mundane reasons not to settle, as Gibraltar had many disadvantages that were to hinder later settlers. It lacked easily accessible fresh water, fertile soil or a safe natural anchorage on the shoreline. Avienus cited the "shallow draft and dense mud of the shore" as reasons not to land there. Its geographical location, which later became its key strategic asset, was not a significant factor during the Classical period as the entrance to the Mediterranean was not contested by the states of the day. For these