The plant that black tea comes from is called Camellia sinensis, and the leaves are usually dried and steeped in hot water to make them into a beverage. This can be cooled to create iced tea, but you can also make a wide variety of different tea blends with it, with options like Morning Tea and Earl Grey being very popular.
While it contains a wide range of chemicals, black tea is generally considered to be quite good for you when it is consumed in moderation. Along with caffeine, black tea also contains antioxidants, along with a range of other beneficial chemicals that can improve your overall health.