Surveyors are checking to make sure that the Washington Monument is still 555 feet, 5 1/8 inches tall.
The survey is being conducted by the National Geodetic Survey and is the first of its kind since 1999. Surveyors can only access the peak of the monument to check the height when it's covered in scaffolding.
The monument is undergoing work to repair damage from the 5.8-magnitude earthquake that struck in August 2011.
A survey conducted last year at the base of the monument found that it had not sunk any further into the ground after the earthquake, but surveyors want to make sure. Surveyor Dru Smith said he has no reason to believe the height of the monument has changed.
The goal of the survey is to establish a definitive height that can be used as a reference point. Results of the new survey won't be available for around two to three months.
Last weekend, crews turned off the more than 400 lights illuminating the scaffolding on the Washington Monument.
Work to remove the scaffolding is scheduled to begin next week. It will take about three months to take the scaffolding down.
The Park Service said repairs to the exterior of the monument are about 80 percent complete. Work will continue on the lower, exterior portion once the scaffolding is removed. Work to the interior, which is about 30 percent complete, will also continue.
The monument is expected to reopen to the public in spring 2014.
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