National parks: NPS_LDD_Nickel - public domain image

"US Park Ranger Nickel suffered a fatal heart attack while patrolling the Little Ruin Canyon trail on foot in Hovenweep National Monument. The trail Ranger Nickel was patrolling was rocky, steep, and uneven. Ranger Nickel was found unresponsive on the trail by park visitors. Efforts to revive Ranger Nickel were unsuccessful. Ranger Nickel was pronounced dead at the scene."
http://names.lawmemorial.org/officers/n/christopher-nickel.html