Colorado's Rocky Mountain National Park welcomes more than 4 million visitors every year, but this jewel of America's parks has seen more than its fair share of deaths among its tourists. More than 70 people have perished attempting to climb Longs Peak, the park's tallest mountain--some of whom vanished into the wilderness, never to be found. Thousand-foot falls from high rock ledges, hypothermia, avalanches that bury climbers, lightning strikes,...