In Mera, Oleiros, two alignment towers known as brother lighthouses continue to guide navigation in the Coruña Ría since 1917.
The lighthouses stand within the Costa de Dexo-Serantes Natural Monument. The smaller one measures 11 meters high and emits constant red light at 56 meters above sea level. The larger tower reaches 14 meters and projects white light from 81 meters elevation.
Both white octagonal structures are separated by about 300 meters. Between them lies the former lighthouse keeper’s house, now converted into the Aula do Mar visitor center.
The towers entered service in 1917 using gasoline vapor lamps and received electricity in 1932. Their alignment marks the safe channel into the port and avoids reefs in Atlantic waters.
The site belongs to the Natura 2000 network and draws hikers for its ecological and historical value.