The National Law Enforcement Officers Memorial is centered in the 400 block of E Street, NW, Washington, DC and is the nation’s monument to law enforcement officers who have died in the line of duty. The Memorial features two curving, 304-foot-long blue-gray marble walls. Carved on these walls are the names of more than 19,000 officers who have been killed in the line of duty throughout U.S. history, dating back to the first known death in 1791. The Memorial is open 24 hours a day, 365 days a year, and there is no charge to visit. The site is staffed during regular business hours.