The three most prominent mountain ranges, which run parallel to each other from the southwest to the northeast, are the Middle Atlas, the High Atlas, and the Anti-Atlas. The Moroccan coastline, which fronts onto both the Mediterranean and the Atlantic, offers plenty of great beaches as well as a number of fascinating old coastal cities. In the southeast, Morocco's mountain ranges yield inexorably to the desolate expanse of the Sahara. The rivers that flow down this side of the High Atlas support long, narrow, and lush river valleys that resemble linear oases. The climate in Morocco is reliably dry, although small amounts of rain do fall between November and March.
Temperature varies considerably by season and locale.
While the southern and southeastern desert regions can reach extremely high temperatures during the hot summer months, the higher altitudes of the mountains are cool in summer evenings and freezing in winter. Most travellers find the early summer months to be the most comfortable time to visit, as rain is not a threat and temperatures are warm during the day and pleasantly cool at night. BC Rome extended its rule over the area after defeating Carthage in 146 BC, and testimony to its presence still exists in the fine Roman ruins at Volubilis. As Rome fell into decline Morocco was invaded first by the Vandals and then, in the 7th century, by the Arabs. Although external Arab rule lasted little more than a century, the arrival of Islam proved to be a permanent addition to Moroccan culture.