São Sebastião Church

inside a fort with the same name.

The São Sebastião de Castro Marim fort - so named because it occupies the place where a chapel dedicated to São Sebastião once existed - is the best preserved example of what was the extensive system renovation process defensive of the village in the mid-17th century. Its construction is due to King D. João IV, within the scope of the Restoration Wars with Spain, and it would have started as early as 1641. The project transformed the old medieval castle into the most important military square in the whole of the Algarve. The plan of the fort was adapted to the hill on which it was implanted, defining an irregular walled enclosure, which includes five bastions and whose main door is facing the north, in the direction of the town and the castle. This close relationship with the castle of Castro Marim is one of the most important aspects of the works carried out in the village in the 17th century, as the new military system in the locality did not dispense with the old walled enclosure, but integrated it into the new structure.

Although dating from the 18th century, it has an image of the archangel São Gabriel from the 15th century. It has an interesting dome.

Contains an altarpiece evoking the miracles of the saint.