The much-anticipated movie “Oppenheimer” opens today – about the scientist who led the development of the atomic bomb. On “Post Reports,” we’re joining The Post’s Lillian Cunningham on a journey to the site of the bomb’s first test.Read more:White Sands National Park contains a geological rarity: the largest field of gypsum sand dunes anywhere on Earth. The blinding white dunes stretch for miles in every direction, dazzling tourists, inviting selfies and sled rides.But there’s much more to this park than meets the eye. White Sands National Park, one of the newest in the system, is embedded within White Sands Missile Range, the largest military installation in the country. Today the missile range is a testing ground for cutting-edge weapons. It’s also home to the Trinity site, where the first test of an atomic bomb was conducted in 1945. In that instant, the sand beneath the bomb fused into greenish glass. And life changed forever for people living in communities nearby.That same sand also holds evidence of humanity’s origins on this continent. One observant park ranger at White Sands National Park has spent years uncovering footprints delicately preserved in the shifting sand. Those tracks have painted a picture of prehistoric families living alongside mammoths and giant ground sloths. They’ve also raised new questions about just how long ago the first people might have crossed into North America.In this episode of “Field Trip,” Washington Post reporter Lillian Cunningham visits these two very different sites in the New Mexico desert and asks why this landscape has been both safeguarded and sacrificed. Subscribe to Field Trip here or wherever you're listening to this podcast.