Some people collect bottle-caps, others Popsicle sticks, some coins and a large number collect stamps. Collecting is a fun and relaxing way to spend some leisure time.
Most countries issue their own stamps, but belong to an international postal union.
This is why there are similarities among all postage stamps, which makes collecting worldwide stamps extremely fun. There are two basic kinds of stamps, Definitives and Commemoratives. Commemoratives are issued to celebrate an event or person and are only available for a short time. They are bigger, more colorful but no more expensive. Here in the US, the Elvis stamp issued a few years ago was a popular commemorative stamp.