There were sites of pilgrimage, and in some of them the pilgrims provided the main source of income for the area as a whole. Mecca and Medina are famous examples to the present day. St Iago de Compostela, in modern Spain, which houses the relics of St James ("Sant Iago"), is probably the most famous example in Europe. It's worth noting that pilgrimage to Campostela was so popular that a whole network of pilgrimage sites grew up along the various roads from Europe to Compostela and became known as Camino de Santiago or in English the Way of St. James. There are Asian sites of pilgrimage as well, though I can less easily name them. Bodh Gaya is an obvious one, but there are many places of pilgrimage that formed the backbone of the local economy scattered throughout South and East Asia (and possibly Southeast Asia, though I know less about it).