Hallie Busta Box-toting volunteers exit the Dupont Circle Metro station, in Washington, D.C., on Monday.

"The Beach," a giant ball pit by New York firm Snarkitecture that took up residence this summer at the National Building Museum in Washington, D.C., closed on Monday. But that's not the last we'll see of the more than 650,000 translucent plastic balls that filled the installation. This week, volunteers are moving boxes of the balls and roughly 6,000 square feet of mesh netting across town to the Dupont Underground, a planned arts venue in abandoned trolley tunnels underneath the city's Dupont Circle. The below-grade arts space has said it will use the balls as a medium for a yet-to-be announced design competition. In the meantime, volunteers and staff from both organizations are taking all forms of transit to bring the balls to their new home.

On Monday, with a GoPro strapped to one of our reporter's heads, ARCHITECT joined the first of many treks across the city, which included a crowded ride on the city's Metrorail subway system. Watch the time-lapse of our journey below.

“The Beach” Goes Underground