 Unbelievable heat in Las Vegas. I'm Carmen Roberts, Fox News. Las Vegas is sizzling, reaching 115 degrees or more for a record five straight days. According to the National Weather Service, the city hit 119 degrees Tuesday and reached 120 degrees Sunday for the first time in history. A rep for the National Weather Service calls this the most extreme heat wave in the history of record-keeping in Las Vegas since 1937. More than 142 million people...