USPS Waterfalls Forever Postage Stamps US Postal First Class Nature Rock River Park Party Announcement Celebration Anniversary (60 Stamps)

Among nature's most beautiful wonders, waterfalls come in all shapes and sizes, from serene cascades to mighty cataracts. The U.S. Postal Service celebrates the variety and beauty of American waterfalls with 12 new stamps. A waterfall is part of a river or stream where its flow pours over a near vertical rocky ledge or cliff of some height before reaching rocks or a pool below. Waterfalls can be classified by volume, height and width; another popular method is by type, based on the way the water actually falls. One of the most familiar types is the plunge, where the stream falls vertically without making contact with the underlying cliff face; sometimes there are caverns behind the falls carved by earlier erosion. As the name suggests, a fan waterfall resembles the shape of a fan as the flow spreads down the rocks. Other types include the cascade, which breaks into smaller falls as the water descends over a slope of rocks and boulders, and the cataract, where large amounts of fast-moving water plummet over a cliff to create a waterfall of great size and power. A perennial favorite of photographers, amateur and professional, the visual beauty of waterfalls and their natural surroundings is not their only appeal. The sound of the falling water — whether a melodic trickle or a thunderous roar — also draws visitors. The 12 waterfalls featured on the stamps represent many different types found in the United States.