This chapter discusses a number of economic and social factors. It explores changing attitudes to travel, as well as presenting a discussion of how opportunities for travel have increased. The chapter examines changing attitudes to travel, as well as presenting a discussion of how opportunities for travel have increased. Tourism is a global industry involving hundreds of millions of people in international as well as domestic travel each year. The World Tourism Organization estimated that there were 842 million international travellers in 2006. Major changes in the second half of the twentieth century led to the rapid and massive growth of the phenomenon known as modern tourism. Internal tourism can relate to a region within a country, while national tourism considers all forms of tourism within one particular nation or country. Several sociological theories have been put forward in the tourist literature in an attempt to explain motivation.