Flags have existed for over 3000 years. The earliest flags were wooden or metal poles topped with a carving. About 2000 years ago pies of fabric were added to some poles for decoration. Over the next 500 years the free-flying part of the flag became more important. Every country today has its own flag. Many groups and organizations also have a flag which stands for, or symbolizes, the aims of the group. The flag depicts   a world map, centered on the north pole. The map is surrounded by an olive   wreath   symbolizing peace and co-operation. The flag is blue and white. Flags have been in existence for   _  .
500 years more than 3000 years about 2000 years between 500 and 2000 years