What has the most travel in the United States?

The restrictions on U.S. citizens traveling to Cuba lapsed on March 19, 1979; the regulation was renewable every six months, but President Jimmy Carter did not renew it and the regulation on spending U.S. dollars in Cuba was lifted shortly afterwards. President Ronald Reagan reinstated the trade embargo on April 19, 1982. This has been modified subsequently with the present regulation, effective June 30, 2004, being the Cuban Assets Control Regulations, 31 C.F.R. part 515. The current regulation does not limit travel of US Citizens to Cuba per se, but it makes it illegal for US Citizens to have transactions (spend money or receive gifts) in Cuba under most circumstances without a US government Office of Foreign Assets Control issued license.