Tourism is travel for recreational, leisure or business purposes. The World Tourism Organization defines tourists as people "traveling to and staying in places outside their usual environment for not more than one consecutive year for leisure, business and other purposes".

Tourism has become a popular global leisure activity. In 2010, there were over 940 million international tourist arrivals worldwide, representing a growth of 6.6% when compared to 2009. International tourism receipts grew to US$919 billion (€693 billion) in 2010, corresponding to an increase in real terms of 4.7%. As a result of the late-2000s recession, international travel demand suffered a strong slowdown from the second half of 2008 through the end of 2009. After a 5% increase in the first half of 2008, growth in international tourist arrivals moved into negative territory in the second half of 2008, and ended up only 2% for the year, compared to a 7% increase in 2007. This negative trend intensified during 2009, exacerbated in some countries due to the outbreak of the H1N1 influenza virus, resulting in a worldwide decline of 4.2% in 2009 to 880 million international tourists arrivals, and a 5.7% decline in international tourism receipts.