Today, Biden becomes the 13th sitting president to meet the Queen during her reign, joining a legacy of American leaders paying their respects to a global icon and living piece of history.

After meeting the Queen, he'll head to Brussels where he will spend two days meeting with more US allies at NATO headquarters and the European Union, before heading to Geneva to meet with Russian President Vladimir Putin.

He and first lady Jill Biden have a formal audience scheduledwith her at Windsor Castle, her home outside London.

It's her first one-on-one engagement with a world leader since the coronavirus pandemic began. And it's among her first public engagements since her husband, Prince Philip, died at 99 earlier this year.

Biden has spent his first international trip aiming to revive American alliances with the world's richest democracies.