Pont Basculant de la Seyne-sur-Mer

Visitors passing by the Pont Basculant de la Seyne-sur-Mer, a 42-meter-tall observation tower on the Seyne-sur-Mer in France might be startled when they recognize that it doesn't look anything like any other observation tower they've seen in the past. There's a good reason for that.

The Pont Basculant de la Seyne-sur-Mer, completed in 1917, was once a movable railway bridge that allowed ships to pass through the harbor. When the railway was shutdown, the bridge was permanently moved into an upright position and converted to serve its current function.

It was an easy decision, as the bridge had already been constructed and was located in a smart lookout place; it wouldn't have made much sense for the French government to pay to dismantle the structure and then rebuild a new observation space using many similar materials so the bridge was set upright and has been looking out over the countryside since.