Remains of the US bomber base and Atom Bomb Pits, and the remains of Japanese fortifications, are located at North Field. There is a memorial on the old airfield at the loading pits, which are roofed-over with glazed panels in metal framing for safer viewing. Both pits were reopened in conjunction with the 60th Anniversary Commemoration of the Battles of Saipan and Tinian. The pits were originally constructed to load the bombs, since they were too large to be loaded in the conventional manner. The B-29s were maneuvered over a pit with their bomb bay doors open to facilitate loading.