Engineers began scaling the Washington Monument Tuesday to inspect the 555-foot obelisk for damages from the August earthquake.

Though the Monument is structurally sound, Aug. 23’s 5.8 magnitude quake left the monument with several issues – like “cracking and spalling of the exterior marble and underlying stone masonry elements” that need further attention, according to report engineers conducted for the National Park Service. The Monument is closed indefinitely until work is complete.

At about 9:30 a.m. Wednesday, engineers were inside the Monument but had not yet begun rappelling the Monument, Bill Line, spokesman for the park service, said, adding that they would continue throughout the day.

A video posted by the park service with security footage from the observation deck the day of the earthquake shows the Monument shaking and wobbling while visitors rushed down the stairs.