The Arlington 9-11 Memorial 5K will once again be in-person after going virtual last year. This will be the 20th anniversary of the race, which is run in honor of the Arlington first responders who helped at the Pentagon on Sept. 11, 2001, and in support of 9/11-related charities. The race is organized by members of Arlington’s public safety agencies, including the police department and sheriff’s office. The event is scheduled for Saturday, Sept. 11 and around 3,000 people are expected to participate this year, Race Director and Sheriff’s Office Lieutenant Jose Quiroz tells ARLnow. That’s in line with previous years.