People are having more and longer holidays.
People have more disposable income than they used to, so can afford to go on more holidays.
Companies give more paid holidays than they used to. This means people have more free time, so they go on holiday more.
Travel has become cheaper so more people can afford to go on holiday.
Holiday providers now use the internet to sell their products to people directly, which makes them cheaper.
Areas are becoming more popular
Improvements in transport have made it quicker and easier to get to places - no more week-long boat trips to Austrailia for a start.
Countries in more unusual tourist destinations like the Middle East and Africa have got better at marketing themselves as tourist attractions. This means people are more aware of them.
Many countries have invested in infrastructure for tourism to make them more attractive visitors.
Cities, Mountains and Coasts
People are attracted to cities by the culture, entertainment and shopping.
Popular destinations include Rome, Paris, New York and London.
People are attracted to mountain areas by the beautiful scenery and activities like walking, climbing, skiing and snow boarding.
Popular destinations include the Alps, the Dolomites and the Rockies.
People are attracted to coastal areas by the beaches and activities like swimming, snorkelling, fishing and water skiing.
Popular destinations include Spain, Caribbean and Thailand.
Tourism is important to the economy
Tourism creates jobs for local people, which helps the economy to grow.
It also increases the income of other businesses that supply the tourism industry. This helps the economy to grow.
This means tourism is important to the economy of countries in both rich and poor parts of the world.
Poorer countries tend to be more dependent on the income from tourism than the richer ones, e.g tourism contributes 3% of the UK's GNP, compared to 15% of Kenya's.