Longjing tea, translated as Dragon Well tea, is considered the national tea of China. It is grown almost exclusively in the Longjing area of Hangzhou, near the Western Lake.
Cultivation of this tea dates back thousands of years. Mention of Longjing Tea dates back to the first ever tea book, written by Lu Yu in the Tang Dynasty. Tea on the mountains is grown year round, however, harvest, is only taken from mature plants at least 5 years old. Also, the tea is only able to be harvested when the new buds arrive in the Spring, creating a very short window to provide the leaves.
The leaves are then dried my master craftsmen, using a low even heat to prevent the leaves from decaying after they are picked. The tea drier must by skilled, as too much drying will burn the tea, leaving it bitter, while too little will not preserve the harvest.
Longjing has become a symbol of China and its teas. It is usually served to state guests, and is said to have been Chairman Mao's favorite. Other notable recipients of Longjing Tea include Richard Nixon, Henry Kissenger, and Queen Elizabeth.
Longjing is one of many types of green tea that is noted for its health benefits. Green teas contain much higher amounts of antioxidants and have been found to lower LDL cholesterol. Also, many observational studies have noted that people who consume green teas have a noticeably longer life span compared to those who don't. More studies are being done on the health benefits of the tea.
Sources: http://www.teaspring.com/Tribute-Xi-Hu-Long-Jing.asp
and http://en.wikipedia.org/wiki/Green_tea#Potential_effects_of_green_tea_on_health