Exterior lights unexpectedly go dark on Washington monument

The spotlights on the Washington Monument in Washington, D.C., went dark Sunday night, leaving officials trying to determine the cause of the unexpected outage.

"The exterior lights of the Washington Monument are currently out," the National Park Service tweeted on Sunday evening. "We are investigating and will have them restored as soon as possible."

The NPS as of Monday morning had not posted an update on the outage.

The lighted, 555-foot-tall obelisk, on the National Mall, is the tallest structure in the nation's capital and the most well known in its skyline. 

The light issue occurred one day after the National Park Service announced that the monument would closed "until further notice" to protect staff and visitors from the spread of the coronavirus.