CASPER, Wyo. -- It's hard to imagine, in all the silence, that this landscape was dotted with hundreds of thousands of people once.
Right here, oxen pulled wagons through soil. Men and women lugged handcarts over rock.
The constant push of emigrants westward was enough to leave depressions in the ground, swales that can still be seen today.
The Oregon, Mormon, California and Pony Express trails weave through prairie on both private and public land in Wyoming. Some 340 miles of trail are preserved on Bureau of Land Management land, nearly untouched 150 years later.