What can you learn from stamps?We can learn many things about ______ from stamp

Stamp-collecting is a very interesting and useful hobby. You can learn many things about geography and history from stamps. Today more people collect stamps than ever before, and special stamps are often printed for these people. If you buy a new stamp and put it on an envelope on the first day it is sold, the envelope may be worth a lot of money in the future. Many stamp collectors go to the post office when new stamps are being sold.
   People all over the world like collecting stamps. Indeed, some doctors say that everybody likes collecting something. Some children enjoy collecting the tops of matchboxes and others like collecting coins. Collecting paintings is a hobby of many rich men, but they often do this to make money. They keep the paintings for a short time and then sell it at a much higher price. The ordinary people, of course, don’t want to do like that. They collect stamps for pleasure.