Fuzhou Majiang Sea War Memorial stands near the old Mawei arsenal, where the Battle of Fuzhou opened the Sino-French War in 1884. The memorial includes Zhaozhong Temple, dedicated to those killed in the battle, and exhibits on the naval defeat that devastated China's Fujian Fleet.
It is a specialised stop, but a worthwhile one if you are interested in modern Chinese history, naval power, or the treaty-port era. Pair it with other Mawei sights rather than treating it as central Fuzhou sightseeing.