Nosy Alañaña Light, Maritime beacon in Toamasina Province, Madagascar.

Leuchtturm l'île aux Prunes is an octagonal concrete tower standing 60 meters tall with a black lantern and observation gallery at the top. The structure sits on the small island of Île aux Prunes and marks an important navigation point for maritime traffic along Madagascar's eastern coast.

This beacon began operating in 1933 to improve maritime safety along Madagascar's eastern coast. It was built to address the navigational challenges faced by ships passing through these waters.

The island's Malagasy name, Nosy Alañaña, means Isle of Prunes, and the French form Île aux Prunes is still used for the lighthouse. The islet itself is uninhabited, so the tower is a working aid to navigation rather than a lived-in site; boats from Toamasina pass it on the crossing north-northeast.

The light flashes white signals every 25 seconds and can be seen from ships about 23 nautical miles away. Access to the island depends on weather conditions and sea state, so plan accordingly for any visit.

The French sources give the tower's height as 60 metres and rank it 28th in the world, tied with the Eckmühl lighthouse in Brittany; the English article places it 24th. Its octagonal reinforced-concrete shaft was erected between 1931 and 1933 on an uninhabited islet.