WELDON SPRING, Mo. -- Talk about making lemonade out of lemons: making a fantastic view out of a rock-covered pile of radioactive waste.

That's just what the U.S. Department of Energy has done at the Weldon Spring Site Interpretive Center on Highway 94, west of St. Louis.

In 1941, the Army displaced the towns of Hamburg, Howell and Toonerville and opened a DNT and TNT processing facility on the land. On a good day, workers made 1 million pounds of the stuff at the plant. In the 1950s and '60s, the U.S. Atomic Energy Commission took over and processed uranium ore there.

Fifteen years of inactivity and 17 years of cleanup later, the site opened in 2002 with some who worried about its safety. The Energy Department insists otherwise. Putting a fence around the area is the worst message it can send to the community, officials have said, so they've designed the site to attract visitors.

It offers an interpretive center that chronicles the history of the site, a 150-acre prairie, which makes it the largest of its kind in the St. Louis area, a native flower garden, picnic tables and a meeting room. The 8-mile Hamburg Trail runs through the site and connects the Katy Trail and the August A. Busch Memorial Conservation Area.

The most striking feature of the site is the huge mound of rock looming behind the interpretive center, called the "disposal cell." At 75 feet tall and 1 mile in circumference, it is the highest accessible viewpoint in St. Charles County. From the top of the pile, visitors can see O'Fallon, St. Peters and St. Charles, and on a clear day even the Gateway Arch is visible about 30 miles away.

The view almost makes you forget you're standing on top of 1.48 million cubic yards of low-level radioactive material, including 43 crunched-up buildings from the old processing facility.

Layers of limestone, gravel, dirt, and a "geosynthetic liner" separate you from the waste. The government wouldn't invite you to stand on top of it unless it were safe, said Brendan McGhee, marketing assistant at the center.