The Old Iron Bridge, Grand-Popo, Benin

I made this video in 2021 of a much-photographed historical monument in Grand-Popo, the Iron Bridge while field studying the local history. It was the first firm connection that joined the Grand Popo spit with the African continent. Before it, a ferry served between Heve and Gbecon across the Mono river or lagoon. Despite efforts, I could not find out when and who built the bridge. Right by it there is a modern concrete bridge that is used for the main traffic nowadays. I did not find any information concerning that either. If you have any knowledge of these, please contact me. Thanks!