The death toll from Thailand's worst flooding in half a century reached 506 Sunday, as flood waters inched toward downtown Bangkok, the interior ministry said. By Sunday, authorities ordered evacuations for residents in eight of Bangkok's 50 districts. Across the country, the flooding -- now in its third month -- has affected 25 of Thailand's 64 provinces. Bangkok's central business district is still dry but other parts of the bustling metropolis of 12 million people are inundated.