Not in the Serra de Tramuntana, but qualifies to be on this website as the scenery is excellent as the views towards Cap Formentor and Talaia d'Albercutx are spectacular.
A short sharp and very scenic climb on a narrow road with amazing views.
Starting at the bridge opposite the S'illot beach where costumes are optional, the gradient averages around 9% but reaches 13% in places.
Winds down with the optional detour towards the army base halfway down.
To be aware of
The road is narrow. There are often goats. There are often tourists in rental cars looking at the stunning views, not at you. Occasionally sand on the surface. Slow is better.