Fort of Greta
Angústias, Portugal
The Fort of Greta (also referred to as the Castelo da Greta, Forte da Guia or Forte da Nossa Senhora da Guia da Horta, respectively: Castle of Greta, Fort of Greta or Fort of Our Lady of the Guide) is a fortification, whose remnants are located on the cinder cone of Monte da Guia, along the southern coast of the civil parish of Angústias, in Horta, island of Faial, in the Portuguese Azores.
Fort data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).