18 State Department travel warnings and alerts Americans should know about

The U.S. State Department issued a travel alert for Europe on Monday, saying American citizens should be aware of a continued threat of terrorist attacks throughout the continent.

There are two types of State Department travel notifications: travel alerts and travel warnings. The U.S. Passports & International Division clearly defines the difference between these two terms:

Travel warnings: "We issue a Travel Warning when we want you to consider very carefully whether you should go to a country at all. Examples of reasons for issuing a Travel Warning might include unstable government, civil war, ongoing intense crime or violence, or frequent terrorist attacks. We want you to know the risks of traveling to these places and to strongly consider not going to them at all. Travel Warnings remain in place until the situation changes; some have been in effect for years."

Travel alerts: "We issue a Travel Alert for short-term events we think you should know about when planning travel to a country. Examples of reasons for issuing a Travel Alert might include an election season that is bound to have many strikes, demonstrations, or disturbances; a health alert like an outbreak of H1N1; or evidence of an elevated risk of terrorist attacks. When these short-term events are over, we cancel the Travel Alert."

Europe isn't the only area the State Department has issued a travel alert for, and these are the destinations American travelers should be cautious of when booking travel: