The travel review provider added 30 world cities to its City Guides free mobile app. This brings to 50 the number of global cities covered by the app. TripAdvisor (TRIP - News) says over 1 mil users have downloaded City Guides since it launched in late 2011. Cities added to the guide include: Athens, Madrid, Edinburgh, Milan, Bangkok, Shanghai, Seoul and Istanbul. The feature also includes transit maps for specific cities and custom itinerary advice for Google (GOOG - News) Android phone users. TripAdvisor shares fell 1.7%.