Cannabis is a flowering plant with three main varieties, namely Cannabis sativa, Cannabis indica and Cannabis ruderalis. All three of these were originally harvested in South and Central Asia where they were used for thousands of years as a source of fibre (we call hemp) and seed oil. Cannabis is well propagated in the tropical and temperate areas of the world but these days it can be grown in almost any climate, and is increasingly cultivated through indoor hydroponic technology. Cannabis was also widely used for medical treatment and of course, recreationally.