Tour Dreyfus is a squat cylindrical stone tower on Pointe des Roches, the rocky headland at the western end of Kourou's old town. In the era before radio, it was used to relay semaphore signals between the mainland and the penal administration on the Îles du Salut — a visual communications link across 14 kilometres of open water.
The tower is named, inevitably, after Alfred Dreyfus, though his connection to Kourou is indirect: he was held on Île du Diable offshore, not in the town itself. The structure is modest but the setting is good — you get a clean view across the bay towards the islands from the point, and at low tide there are rock pools to pick through. It's a short walk from the Vieux Bourg dock.