Complex sentence: Pendleton pointed out that radioactivity can concentrate in "hot spots" such as the rolling dunes of Snow Canyon, a natural reservoir for windblown material, which was where much of "The Conqueror" was filmed.
Split into simpler sentences: Pendleton pointed out that radioactivity can concentrate in "hot spots" such as the rolling dunes of Snow Canyon, a natural reservoir for windblown material. It was the place where much of "The Conqueror" was filmed.