By far the most popular and most consumed drink in the world is water, but it may come as no surprise that the second most popular beverage is tea. Although tea was originally grown only in certain parts of Asia - in countries such as China, Burma and India - it is now a key export product in more than 50 countries around the globe. Countries that grow tea, however, need to have the right tropical climate, which includes up to 200 centimetres of rainfall per year to encourage fast growth, and temperatures that range from ten to 35 degrees centigrade. They also need to have quite specific geographical features, such as high altitudes to promote the flavour and taste of the tea, and land that can offer plenty of shade in the form of other trees and vegetation to keep the plants cool and fresh. Together these conditions contribute to the production of the wide range of high-quality teas that are in such huge demand among the world's consumers. There is green tea, jasmine tea, earl grey tea, peppermint tea, tea to help you sleep, tea to promote healing and tea to relieve stress; but above all, tea is a social drink that seems to suit the palates and consumption habits of human beings in general.