A record number of more than 31,000 runners are expected to participate in the Marine Corps Marathon Sunday morning when the 105 mm howitzer fires off the starting signal.

The 31st annual run has become a staple of Washington-area runners and has earned several nicknames, including the “People’s Marathon” because of the absence of prize money, and “The Marathon of Monuments” because the course travels through the most majestic memorials of the national capital.