<human>:  Which countries require a visa for U.S. passport holders?
<bot>: The countries that require a visa for U.S. passport holders vary depending on the passport holder's nationality and the country they are visiting. Generally, countries that require a visa for U.S. passport holders include Afghanistan, Algeria, Angola, Bangladesh, Benin, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Republic of the Congo, Cote d'Ivoire, Djibouti, Equatorial Guinea, Eritrea, Ethiopia, Gabon, The Gambia, Ghana, Guinea, Guinea-Bissau, India, Iran, Iraq, Jordan, Kenya, Kosovo, Lebanon, Liberia, Libya, Mali, Mauritania, Morocco, Nepal, Niger, Nigeria, North Korea, Pakistan, Palestine, Russia, Rwanda, Sao Tome and Principe, Senegal, Sierra Leone, Somalia, South Sudan, Sudan, Syria, Tanzania, Togo, Tunisia, Turkmenistan, Uganda, Ukraine, Venezuela, Yemen and Zimbabwe.