The Castle of Moinhos (also known as the Alto Fortress) is a 16th-century fortification set on the hill above Angra, now reduced to ruins but accessible via a marked walking path from the city center. The approach takes about twenty minutes on foot and passes through the edge of the Monte Brasil nature reserve. The ruins themselves are modest — walls, a gateway, the footprint of towers — but the reason to come is the view from the top.
Standing at the castle ruins, you can see the full extent of Angra do Heroísmo laid out below: the grid of Renaissance streets, the cathedral tower, the harbor and its protective arm of land, and beyond that the Atlantic. On clear days the central volcanic massif of Terceira is visible to the west. The volcanic terrain around the fort is scrubby and windswept; the path continues further up Monte Brasil for those who want a longer walk. Early morning or late afternoon are the best times — midday in summer can be hot and exposed, and the light for photographs is flat.