Mount Everest is the world's highest mountain and one of the most dangerous, having claimed more than 200 lives over the past century. Until last year's fatal avalanche, the deadliest year in recorded history was 1996: 15 people died, eight of them in a single blizzard. That disaster has been chronicled in at least five books, two documentaries — and now, an opera premiering in Dallas, Texas, simply called Everest. NPR