Just as the $1 and $2 definitive postage stamps issued in March 1972 remind us of our urban centres, Canada's new medium value denomination remind us of the tremendous variety in our nation's terrain. The immensity and diversity of Canada are almost incomprehensible; few other nations have the challenge of the seas, the woodlands, the prairies, the mountains and the north. Our country, a land of breathtaking beauty, has inspired Reinhard Derreth, of Vancouver, to create these designs which capture something of the vastness and beauty. A prairie mosaic was chosen for the 20c. stamp by which we are reminded of the immenseness and of the diversity of the prairies. While wheat is the basic crop, other agricultural products such as oats, barley, rye, alfalfa and sugar beets also have their place. South and west of the main wheat-growing areas ranching is important. The importance of prairie agriculture to Canada's economy cannot be overstated; Canadian grain and beef have an important place on domestic and world markets.