Here's Why the Washington Monument Went Dark

An investigation into a temporary overnight blackout at the Washington Monument in D.C. has revealed it was caused by a "faulty timeclock," its caretakers have said.

National Park Service (NPS) officials, who look after national monuments, launched the probe into the issue after social media users shared photographs of the obelisk in the dark overnight on Sunday.

In a statement on Monday, the service said the timeclock was behind the problem and that the lights would be switched on manually until it is replaced.

"The lighting outage at the Washington Monument was caused by the failure of the timeclock that turns the lights on each evening and off in the morning," it said.

"While the faulty timeclock is being replaced, the lights will be operated manually to ensure the monument is lit each night."

Last night’s lighting outage at the Washington Monument was caused by the failure of the timeclock that turns the lights on each evening and off in the morning. While the faulty part is being replaced, the lights will be operated manually to ensure the monument is lit each night. pic.twitter.com/TIJLrKT5AO

— National Mall NPS (@NationalMallNPS) January 25, 2021

Officials had already confirmed there was a problem at the 555 foot (169 meter) tower.

"The exterior lights of the Washington Monument are currently out," it tweeted in the early hours of Monday. "We are investigating and will have them restored as soon as possible."

Pictures posted on Twitter and local media reports suggested the issue had not affected the red-flashing lights that alert aircraft pilots of its presence.

WUSA9 anchor Lorenzo Hall was among those to share a picture of the monument shrouded in darkness in the National Mall, a sight he described as "Creepy!"

Creepy! No lights on the Washington Monument tonight. @NationalMallNPS trying to figure out why... @wusa9 pic.twitter.com/RtQCMcddyf

— Lorenzo Hall (@LorenzoHall) January 25, 2021

The monument was closed on January 11 ahead of Joe Biden's inauguration ceremony nine days later. That closure has been extended "to protect staff and visitors from the spread of COVID-19," NMMP announced on Saturday.

Problems with the lighting and the closure of the monument site are not thought to be linked, Baltimore TV news station WJZ-TV reported on Monday.

The monument, a tribute to former President George Washington, was designed by Robert Mills and completed by Thomas Casey and the U.S. Army engineers.

According to the NPS' official website, Mills had intended the structure to stand 600 feet tall, but Casey made the height of the structure ten times the width of the base,

"The structure was completed in two phases of construction, one private (1848-1854) and one public (1876-1884)," the website's entry on the monument reads.

"Built in the shape of an Egyptian obelisk, evoking the timelessness of ancient civilizations, the Washington Monument embodies the awe, respect, and gratitude the nation felt for its most essential Founding Father."

A three year project to repair the tower was completed in 2014 after an earthquake of magnitude 5.8 struck about 90 miles southwest of Washington, D.C. in 2011.

Washington Monument seen at dusk
File photograph shows the Washington Monument from the U.S. Capitol building at dusk on January 16, 2021 in Washington, D.C. Engineers are working to fix a faulty timeclock at the tower. Samuel Corum/Getty