The State Department has several web sites that warn American travelers of possible dangers overseas:

Curent Travel Warnings - Here’s a list of countries that the State Department recommends that Americans should not travel to.

Public Announcements - The State Department also publishes information about terrorist activity and other risks in countries around the world.

Consular Info Sheets - Nearly every country in the world has information written about it and its government, economy, and embassy.

The Centers for Disease Control and Prevention provides health concerns for traveling abroad:

Health Information - Find health info about Europe including typical diseases, suggested vaccines, and health tips.

Travel Advisories - Travel health warnings and precautions, including outbreaks.

CDC Homepage