The prosperity of South Arabia encourages the Romans to refer to it as Arabia Felix (“happy Arabia”). Increased trans-Arabian trade stimulates the growth of cities that service the trains of camels moving across the desert. The most prosperous of these—Petra in Jordan and Palmyra in Syria—are relatively close to markets in the Mediterranean region, but small caravan cities develop within the Arabian Peninsula as well. The most important is Mecca, which also owes its prosperity to certain shrines in the area visited by Arabs from all over the peninsula.