The Gamboa Northbound Rear Lighthouse is located along the Chagres River approximately 6 km (4 miles) west of the town of Gamboa, Panama. It marks the approach to Gatun Lake from the south as ships transit the Panama Canal. The lighthouse is an 18 metre (60 foot) tall concrete tower. It is painted white on the front side (unsure about the rear). As with other lighthouses along the route of the canal, it was constructed between 1904 and 1914 during the original construction of the canal and was activated in 1914. It remains an active light. Photos taken in March 2016 and the bottom photo shows its proximity to the Gamboa Northbound Front Lighthouse.