A closer look at one of the little watchtowers that project from the Castelo do Queijo on Porto's Atlantic seafront. Officially named the Forte de São Francisco Xavier the coastal fortress was built in the 1660s to defend against the Spanish. This corner of the fort overlooks the beach at Matosinhos.
As far as I know the fortress gets its name from the rock it was built on and has little to do with cheese. Whatever the case it was deemed fairly useless from the start as the area it defended was probably to exposed and rocky to land a fleet on anyway.