The U.S. opened its doors to international travelers after more than 18 months of COVID-19 restrictions.

The U.S. opened its doors to international travelers on Monday after more than 18 months of COVID-19 restrictions, and some airports across the world celebrated the milestone with pomp and circumstance.

Starting Monday, fully vaccinated international travelers will be permitted to enter the U.S. as long as they show proof of inoculation and present a negative COVID-19 test that was taken within three days of travel. The new policy, which was first announced last month, applies to both land borders and air travel. ...