The message in this stamp design is the breadth of information one can gain from a stamp collection. A child is able to use a stamp collection as a springboard to many other forms of learning. Not only is there actual information on each stamp that improves knowledge of the world around, but assembling a collections allows the opportunity to let one's mind wonder. Stamp collections may be keyed to a single nation or region of the world. Other types of collections focus on a single topic or theme, such as space exploration, sports, a narrow or wide range of plants or animals, quilting, or auto racing. The range of possibilities, with more than 475,000 stamps issued worldwide since 1840, is endless.