Even with the ongoing global economic downturn, the world economy is growing. This economic growth is being led by the so called emerging economies' e.g. China, Russia and India. With economic growth more individuals are removed from poverty and are able to afford to go on holiday. People can afford holidays when there disposable income increases.

The amount of money left over after all bills are paid for.

Most countries now have laws stating that companies have to give their employees paid leave. In the EU the minimum amount of paid holiday is 28 days. If you add on weekends, this is nearly six weeks of paid holidays. Because of the extra paid holiday more people now have the time and money to be able to go on holiday.

Over the past 50 years the relative cost of transport has fallen and the ease of moving between countries has increased. Car ownership has increased, new train networks have been built and new airports opened. In the last decade low-cost airlines have emerged and increased tourism.

Offer cheaper flights that normal airlines by removing added extras like airport check-in, in-flight meals, checked baggage and seat selection. The growth of transport has meant people can go on more holidays and also go on shorter holidays (weekend breaks).

We are now saturated with advertising on bill boards, in magazines, on TV and increasingly online. These adverts make us aware of new destinations and persuade us to visit new places. There has also been a growth of TV programs just about holiday destinations.

The emergence of credit cards has made it much easier to pay for holidays and it has made it easier for people to buy things once on holiday. They remove the worry of carrying large amounts of money and the time of exchanging currencies.

In recent decades the quality and quantity of accommodation has improved. Accommodation can vary from basic shared dormitories to luxury hotel suites. The increased variety and quality mean more people are now comfortable about traveling abroad.

Booking flights and hotels is now much easier. You can use a travel agent, but increasingly more people are going online to book their own flights and hotels and flights either directly or through agents. It is also possible to look at customer reviews (www.tripadvisor.com) so you can assess the quality of hotels, tours, etc.

Improved communication has not only made booking holidays easier, it has also meant people can now keep in contact much easier while abroad. This has removed the worry from many families. You can now update your status on Twitter or Facebook or send an e-mail or text to family letting them know where you are or what you are doing.

More and more people now have a passport. In previous years Chinese citizens were not allowed passports to travel overseas, now they are. It is now easier to get visas to visit new destinations and for travel between some countries a visa is not needed.

English is slowly become an international language - it is the most widely spoke second language. As the number of English speakers increase, more and more people are confident about going on holiday and knowing that they will be able to communicate. As the tourism industry develops the amount of multi-lingual guides is also increasing so it is possible to visit a foreign country and go on a tour in your native language.

New golf courses, swimming pools, sports stadiums, theatres, etc. are constantly being opened. This has increased the amount of leisure and sport, but also tourism. People now go on golfing holidays, sports tours or cultural breaks.

Even though the retirement age may be increasing in some countries, most people now do retire. Retirement has been made possible with the introduction of pensions and a rising life expectancy. People are now living longer and are able to support themselves. This has meant that people now have more opportunities to travel after their working life.

In most developed countries the fertility rate is declining. Smaller families now mean that it is much easier and much cheaper to take holidays.

In years gone by many societies have been based on subsistence farming. This has meant that people have to grow and tend their own crops and animals. With the advent of commercial farming and supermarkets, people no longer need to farm so are free to go on holidays.

As the world's population grows, now about 7 billion, there are obviously more people who might go on holiday

Tourism used to be seen as an expensive luxury for the wealthy, now it is seen as a natural yearly ritual by many

As communication and transport improve, it has become easier to hear about and travel to, more remote destinations. Destinations that once seemed out of place e.g. Antarctica or the Amazon Rainforest are now common destinations. With new destinations being discovered all the time, more and more people are going on holiday and visiting these places.

Increased incomes and rising affluence in places like Chin and India mean there are now 100's of millions more potential tourists than several decades ago

It has become easier for women to engage in tourist activities