10. Oakland, California
Sadly, Oakland is yet another California city that has gone downhill due to difficult economic times and high crime rates. And even though this city enjoys Mediterranean climes with an average of 260 sunny days per year and stunning vistas of San Francisco Bay, on the flipside it suffers from horrible traffic congestion, poor air (the pollution index is 190-percent worse than the national average), and escalating crime, making it one of the most dangerous cities in the U.S. The national crime rate in Oakland is a whopping 469-percent higher than the U.S. national average with gun-related crime at the top of the list.