Mannez Lighthouse stands on the northeastern tip of Alderney, marking the headland above the Alderney Race — the treacherous tidal passage between the island and the French coast of Cap de la Hague. The 37-metre tower is a Trinity House lighthouse built in 1912, automated since 1997 and no longer open to the public, but the walk out to the headland is worthwhile.
The landscape around the lighthouse is open and windswept, with the quarry works to the south and the coast dropping steeply to the sea on the east side. On a clear day, the French coast at Cap de la Hague is visible a few kilometres away. The Race itself is visible in the water: you can see the tidal stream running as a distinct band of disturbed water, and on spring tides the current can be seen and heard from the shore.