6. Karachi, Pakistan
Several terrorist and sectarian attacks in Karachi since 2011 have elevated the Pakistani city on the danger list. Both U.S. and UK citizens have been urged to keep a low profile and avoid large gatherings and public places, especially on Fridays, which are a Muslim holiday. According to the BBC.co.uk Karachi is also the most dangerous city in the world for journalists with Taliban terrorists carrying out an attack on a TV station in the southern port city last June.