Britain's Queen Elizabeth II welcomed US President Joe Biden to Windsor Castle in June 2021.
It was her first one-on-one engagement with a world leader since the start of the Covid-19 pandemic. And it was one of her first public engagements after the death of her husband, Prince Philip.
During the Queen's 70-year reign, there were 14 US presidents. She met with all of them except for Lyndon B. Johnson.