A Red Tibetan Mastiff puppy has become the world's most expensive dog after being sold for almost $1.6 million. Tibetan Mastiffs thought to be one of the world's oldest breeds, and legend has it that both Genghis Khan and Lord Buddha kept them. More recently, however, they have become highly-prized status symbols for China's new rich. The dogs are thought to be a pure "Chinese" breed and they are rarely found outside Tibet, giving them an exclusivity that other breeds cannot match.