Mystery solved: Washington Monument went dark because of faulty light timer

The National Park Service says the Washington Monument – a beacon in Washington, D.C., skyline – went dark Sunday night because of a faulty light-timer switch. 

NPS spokesperson Mike Litterst acknowledged the problem to Washingtonian, telling the magazine an automatic timer turns the lights on and off every evening and morning.

He said Monday that the lights will be operated manually "to ensure the monument is lit each night," until an electrician can replaces the malfunctioning timer.

Being the tallest building in D.C., the unlit monument became evident quickly. However, the red aviation lights atop the structure remained functioning on a different power source. 

The 555-foot-tall obelisk is on the National Mall in the nation's capital. 

"Sometimes it's the timer, sometimes it's a breaker gets tripped, sometimes it’s a loss of power from PEPCO – pretty much like your house, only a lot more noticeable when it happens," Litterst also said. 

The monument closed before the Jan. 20 inauguration and will remain closed to prevent the spread of Covid.