Arlington National Cemetery's guided history tours will continue through November, and the latest excursion will feature sites relating to the Memorial Day holiday and World War I.

The World War I and Memorial Day tour is scheduled for May 21 and begins at 11 a.m. The combined trolley and walking tour will begin at the Arlington National Cemetery Welcome Center and travel the cemetery exploring more than a half dozen sites relating to Memorial Day and the first world war.

"This month's theme is specifically for Memorial Day and World War I because it is the centennial anniversary of America's involvement in World War I," said ANC Public Affairs Specialist Courtney Dock.

"In conjunction with the new (World War I) exhibit in the Welcome Center, we're going to talk about how World War I changed Arlington National Cemetery and how America changed and how we honor our war dead."

One stop on the tour will be at the Tomb of the Unknowns. The original Unknown Soldier was an American service member killed during World War I. That Soldier was buried in Arlington on Nov. 11, 1921. Other sites on the itinerary are the graves of Brig. Gen. Montgomery Meigs and Cpl. James Tanner; the old amphitheater is now named after Tanner; the Civil War unknown vault, Sections 1 and 2 (Civil War officers sections) and Section 13.

Meigs began the process of acquiring the property which became Arlington National Cemetery. Tanner was a wounded warrior veteran of the Civil War and became a veteran advocate in the late 19th century.

The two-and-a -half hour tour is free and open to the public. To register, go to https://www.eventbrite.com/e/memorial-day-history-tour-at-arlington-national-cemetery-tickets-34254205250?aff=erelexpmlt.

All the Arlington National Cemetery social media sites also have the tour registration information.

"This is just one of our monthly history tours. We have tours from now until November," Dock said. "Each month, there is a theme, so June's history tour will focus on Army history in support of the Army birthday, and July is an explorers and pioneers tour."

As part of the explorers and pioneers tour, guests will visit the final resting places and memorials of American astronauts at the cemetery.

Other branches of the military will be the topics of the tours throughout the summer and autumn.