(HawaiiNewsNow) - The National Park Service begins a five-day assessment of the exterior of the Washington Monument.
Engineers will rappel down from the top and hit the marble gently with a hammer looking for problems.
The park service already knows the monument was damaged by the Virginia earthquake on August 23rd.
Four cracks were found in the marble after that quake, especially near the top.
Pools of water were found inside the monument after Hurricane Irene.
And, with some mortar having popped out, you can see sunlight inside the monument above 450 feet.
The Washington Monument is 555 feet tall.
Its walls are 15 feet thick at the base and a foot-and-a-half thick at the top.
The bottom of the monument is 163 years old. The top is 127 years old.
The monument has been closed to the public since the earthquake just over a month ago.