Bonsai is the traditional Japanese art of maintaining trees in a state of miniature, sculpting and pruning them into aesthetically beautiful shapes. The art dates back at least to the 12th century, with evidence that is has been practiced far earlier. The trees grown in this way are identical to their full-sized counterparts, being capable of bearing fruit, living for well over a hundred years, and going through the same seasonal foliage changes.
To learn more about the history and artistry of bonsai, and about how to cultivate them yourself, there are a number of good resources available, such as: The Bonsai Site: http://www.bonsaisite.com/
Mini Bonsai by Kyosuke Gun & Sachiko Iwasaki : http://www.mini-bonsai.com/indexe.html