Family Engineering Day.

WASHINGTON, D.C., FEBRUARY 15, 2013: Meriyam Kapadia, 10, left, Stephanie Ajibola, 10, African American girl next to Meriyam, Isha Kaushal, 11, right from Stephanie, and Rithika Changal, 10, right, next to Isha, watch Jason Cawrse, who is a bridge ingeneer, operating a model of a locks system that explains how the extension of the Panama canal will work. The four girls built small boats of aluminum foil which are used to demonstrate how the canal locks system function. The girls are students of the Girls Excelling in Math and Science (GEMS), a club that started at McNair Elementary School in Herndon and is now in 30 Fairfax County schools and more outside the county, who take a field trip to the National Building Museum's Family Engineering Day. (Photo by ASTRID RIECKEN For The Washington Post via Getty Images)