National Geodetic Survey crew members Roy Anderson, left, and Steve Breidenbach set up survey equipment used to measure the height of the Washington Monument. National Geodetic Survey/NOAA hide caption

itoggle caption National Geodetic Survey/NOAA

Monday night when the lights came on, visitors came to see a glowing Washington Monument. Jonathan Ernst /Reuters/Landov hide caption

itoggle caption Jonathan Ernst /Reuters/Landov