Kamchatka, in Russia's far east, has its very own Death Valley, though it's quite different to its more famous partner in the USA. Due to its location close to the Valley of Geysers, high concentrations of very toxic gases are present and dangerous to anyone in the vicinity. Plants, birds, and animals simply cannot survive here, while humans have been known to get extremely ill with dizziness and fever after being exposed.
The poisonous gases, mostly comprised of hydrogen sulfide, carbon dioxide, and carbon disulphide tend to kill smaller creatures such as birds. Much larger animals, such as foxes, bears, and lynx die after eating the carcasses of the smaller animals. As long as humans evacuate the moment they feel the effects of the gases, they should survive, but we certainly wouldn't be risking it!