Tea has been grown for thousands of years in China and then it  eventually spread to Japan.  When trade routes were opened to China, only the royal houses of Europe received tea as gifts.  Eventually wealthy Europeans took to tea in the middle of the 1600s.  In the 1700s it became available to everyone (though expensive) and tea gardens emerged. 
Tea had made its way to America in the late 1600s by the English and cost a small fortune due to it being heavily taxed -  because of the price there was much smuggling and hence the Boston Tea Party.
Tea wasnt grown in India until in the 1700s by the British East India Company.  However on saying that, a native tea plant was discovered in Upper Assam in the early 1800s. 
 
At the right time, tea leaves are plucked, sorted, steamed or dried and may be rolled.  Its long journey eventually makes it to your tea pot and cup. 
There are three main types of tea: 
Green Unfermented tea, in which heat has been used to kill the enzymes that cause the leaves to ferment and blacken.
Black  Fermented tea, in which fermentation has been encouraged to blacken the tea before firing.
Semi-Fermented  Tea that has been partly fermented.
There are many grades of tea  and hundreds of specialist teas and blends.  All green, black, oolong and white teas mainly  come from the same plant,  the Chinese Camellia.  Different soils, altitudes and climates also produce assorted flavours.
