Support WBURBeyond Sightseeing: You'll Love The Sound Of America's Best ParksPlay07:00Download AudioBill McQuayChristopher JoyceJune 29, 2016 ShareGreat Sand Dunes National Park sits at the base of the Colorado Rockies. The dunes soak up sound like a sponge, but human noise can still be heard. (Dana Orlosky/Flickr)