Gaithersburg’s International Latitude Observatory turns 120 – celebrate with activities related to the geodetic science that was done at the site. Tours of the park at 12:30 and 2:30, tours of the Observatory, hands-on activities & birthday cake at 1:00. Visit with the National Geodetic Survey, part of NOAA and the agency that first had oversight of the Observatory, will be here with hands-on activities and displays.