Nations, especially those with a lot of citizens travelling overseas for business or tourism, are increasingly active in providing these foreign travelers with timely warnings on the dangers of visiting certain places. This is all the result of the growth in Risk Management (measuring and dealing with various risks). This has become a major industry since the 1960s. Most of the work is not very newsworthy, so the general public knows little of it. But one aspect of Risk Management, the lists of the most risky countries for tourists and business travelers, does have popular appeal and businesses and governments often purchase more detailed analysis for use within their organizations or to let foreign travelers know where to be careful.
The top ten nations (in terms of their "Terrorism Risk") is not difficult to compile. For most of the last decade this list has included Iraq, Afghanistan, Pakistan, Somalia, Lebanon, India, Algeria, Colombia, and Thailand. More important is the fact that in most of these places the risk is confined to small parts of the countries. Some (Iraq, Afghanistan, Pakistan and Somalia) countries have long suffered high numbers (several thousand a year) of terrorism related deaths. The major factor for the ranking is the amount of terrorism mayhem going on in the nation. For example Lebanon didn't suffer that many deaths, but it's potential for large scale terrorism grew because of the thousands of rockets, and other weapons, Iran has shipped in to its proxy; Hezbollah. Thus tourists are warned to avoid areas controlled by Hezbollah. India has several terrorist groups operating, most of them non-Moslem, and the resulting violence led to over a thousand deaths in 2014. Then again, that's in a nation of over a billion people (Iraq has 25 million). Algeria, Colombia and Thailand are still considered “terrorism hotspots” but terrorist violence in all three has been declining.
Israel, for example, is usually listed as having a terrorism problem, mainly because of all the terror groups trying to attack, them, but failing. In some recent years there were no terrorist attacks inside Israel at all, but there were dozens of rockets fired in from Lebanon and Gaza. These caused few casualties, but because of the many Islamic radical groups dedicated to the destruction of Israel, the potential of major terrorist mayhem is large.
One of the best public warning efforts is carried out by Britain, whose government maintains a continuously updated list of visitor risks in 225 countries and territories. While some of these warnings apply more to British citizens (because of past history with that nation) all warning data is useful to tourists from any country. The British government provides maps with colors to denote what is safe (green, which is most of the world) and red (which is often very small areas).