Several European countries have issued travel warnings to their citizens: if you go to Cuba, you’ll need to apply for a visa to visit the United States. For most Europeans, traveling to the U.S. is an easy process. They qualify for the U.S. Visa Waiver Program (ESTA), meaning they just have to fill out an online form. However, U.S. law denies normally eligible individuals access to ESTA if they have visited countries on its State Sponsors of Terrorism list. Cuba was added to the list last year by Doland Trump and has been kept on it by Joe Biden, even though there is no evidence Cuba sponsors terrorism.