Monday marks the 155th observation of Memorial Day in the United States as the nation honors those who have lost their lives in service to the country.
Recognized annually on the last Monday in May, this year the holiday falls on May 29.
President Joe Biden will mark the day at Arlington National Cemetery, where about 400,000 people - veterans and their eligible dependents - are buried. He will lay a wreath at the Tomb of the Unknown Soldier and deliver an address.
'As a nation, we undertake a sacred ritual: to reflect and to remember,' Biden said in his remarks last year.
The holiday was first widely observed in 1868 as the country recovered from the American Civil War. It became a federal holiday over one century later in 1971.
Since the Revolutionary War ended in 1783, over 646,000 American troops have died in battle, while over 539,000 died from other non-combat related causes, Military.com reported in 2020.
While some observations of Memorial Day, particularly in and around Washington, are marked by solemnity, many Americans spend the unofficial start to summer celebrating over the weekend with barbecues and trips to the beach.
More than 42 million Americans were expected to travel over the weekend, according to the travel organization Triple-A, marking what was expected to be the third busiest Memorial Day weekend since 2000, when AAA started tracking holiday travel.
Transportation Secretary Pete Buttigieg held a news conference last week about Memorial Day weekend, which he said would be 'a test of the system.'
'More Americans are planning trips and booking them earlier, despite inflation. This summer travel season could be one for the record books, especially at airports,' said Paula Twidale, senior vice president of AAA.
Last year, thousands of flights were canceled or delayed over Memorial Day weekend.