Every country has its share of beautiful national parks recognized for their unique scenery. To help conserve these sites, the United Nations declared that such locations be preserved and protected.

This year the U.N. Postal Administration is issuing a set of six stamps and three Prestige Booklets dedicated to U.S. national parks titled “World Heritage USA.” The stamps were released Thursday.

The stamps feature Yosemite National Park, Hawaii Volcanoes National Park, Great Smoky Mountains National Park, Yellowstone National Park, Olympic National Park and Everglades National Park.

Yosemite, in California’s Sierra Nevada, embraces spectacular mountains and valleys. The park includes giant sequoia trees, the world’s largest.

Hawaii volcanoes were created when molten rock pushed through the Earth’s crust. Over millions of years, eruptions built up these volcanoes.

The Great Smoky Mountains are located in North Carolina and Tennessee. The forest there exudes water vapor that creates a smoke-like haze surrounding the area.

Yellowstone is a natural forest in Wyoming. Its hot springs, geysers and canyons make it a place of unrivaled beauty.

Olympic is located in the northwest corner of Washington state. It is dominated by Mount Olympus, which gives the park its name.

Everglades is a fragile ecosystem in southern Florida. The variety of water habitats has made it a sanctuary for a number of birds and reptiles.

The World Heritage USA stamps and booklets are available by calling (800) 234-8672.