Marseille, France's sunny second city, is a beguiling place. A major Mediterranean port, it beckons to urban wanderers and anyone enthralled by cities in all their multiplicity. Marseille's ancient streets tell stories of fires, plagues, wars, decay, and regrowth. Waves of people of diverse ethnic and religious backgrounds have made their way there, and many have found homes for themselves. Although the city hosts visitors from around the world,...