Cerro de la Vigía is the hill behind Trinidad, reached by a steady walk up from the edge of town. The reward is a broad view over the colonial rooftops, the surrounding hills, and the Caribbean coast beyond.
Go in daylight, when the route is straightforward and the view is clearest. The walk passes residential streets before climbing toward the area near Discoteca Ayala, so it pairs naturally with the cave nightclub if you are already heading that way.