To run a 26.2-mile marathon along the Charles River starting/ending at Weeks Footbridge, you can run either 4 bridge
loops in this order (Arsenal-Science Museum 12.5 miles + Eliot-Longfellow 9.2 miles + JFK-BU 3.8 miles + JFK-Weeks 0.7
miles), or 3 bridge loops in this order (North Beacon-Science Museum 14.2 miles + Arsenal-Harvard 9.7 miles + Eliot-Weeks
2.3 miles). Also, 2 North Beacon-Longfellow bridge loops equals 26.4 miles (13.2 miles/loop).