This chapter traces the historical development of tourism, identifying the key influences on the growth in the scope and scale of tourism globally with a specific focus on socio-cultural factors. Acknowledging that tourism (travel) has a history as long as humankind, it identifies key periods in its development, from pilgrimage in the Middle Ages to the Grand Tour and the spa tourism of the seventeenth and eighteenth centuries. The nineteenth century is considered key to the emergence of modern mass tourism with the development of the seaside resorts and the influence of Thomas Cook in the emergence of the travel industry. The chapter then brings the history of tourism to the present day through a discussion of tourism in the twentieth century and into the twenty-first, focusing on the growth of mass tourism.