Travel Warnings from State
If you are an American citizen planning to travel abroad, you may want to check the travel warnings issued by the State Department http://www.state.gov for 41 countries around the world. This does not include weather-related alerts, or the worldwide travel warning issued by the same government department.
There is a feature where you can sign up to be notified if State issues a warning for a country you intend to visit. Most of the countries with warnings are places that are not high on most tourist's wish lists, but there are also some surprises. While you would have to live in a cave to not know that visiting Syria or Yemen right now can be dangerous (because, in part of carpet bombing of certain areas undertaken or financed by Russia or the U.S.,) you may not be aware that places closer to home such as Mexico also merit a warning, mainly because of crime and kidnapping, not terrorism.
Many countries in Africa, the Middle East and Asia merit warnings, as do some in Europe (Ukraine) and Latin America. Diplomatic departments tend to err on the side of caution, so you may be tempted to disregard these warnings. Still, they can contain some useful information about particular things to watch out for.
Other governments issue similar travel warnings for their own citizens. It does make one wonder why the world has, over the last few years, become a much more dangerous place. Could it have anything to do with the foreign policies pursued by the major powers?