Americans made over 93 million visits to foreign countries in 2018, a 6.3% increase over the previous year. So far, 2019 appears to be on pace to be an even busier year for Americans traveling abroad. While international travel is growing in popularity, there are parts of the world that the U.S. government urges American travelers to avoid.

The U.S. Department of State has four advisory levels for travelers: level 4 – do not travel; level 3 – reconsider travel; level 2 – exercise increased caution; and level 1 – exercise normal precautions. 24/7 Wall St. compiled a list of the 26 nations for which the State Department has a standing level 3 or level 4 warning to identify the countries the U.S. government does not want you to go to. All listed travel advisories are current as of October 1, 2019. We also reviewed World Bank data on population and GDP per capita for the most recent available year.

The countries on this list span the globe - from Africa and the Middle East to Latin America and Southeast Asia - and despite their geographic distance, their problems often manifest in a similar way.

The prevalence of violent crime is one of the most commonly cited explanations as to why a particular country has standing level 3 travel warning from the State Department. In many countries on this list, armed robbery, kidnapping, and carjacking are relatively common occurrences. Two Latin American countries on this list are even home to cities with some of the world’s highest homicide rates - here is a list of the most dangerous cities worldwide.

In addition to crime, conditions like political instability, civil turmoil, and persistent terrorist threats - many of which target Western travellers- create dangerous travel conditions. Problems like these are particularly common in African and Middle Eastern countries on this list. Often, these countries are also among the poorest in the world and lack the necessary law enforcement and health care resources to adequately respond to unpredictable outbreaks of violence. Here is a look at the world’s 25 poorest countries.

In rarer cases, when a country has a standing level 4 travel warning, the potential dangers to American travelers are even more extreme. Several countries with level 4 warnings are in the throes of outright civil war. Others rank as unsafe for American tourists because they have authoritarian regimes that have no diplomatic relations with the United States. In these places, Americans are often detained and imprisoned without reason - and without an embassy or consulate, the U.S. government is unable to provide support services.