The little white fort of Sao Joao do Carvalhao stands on the headland at the eastern end of the seafront, the only piece of pre-resort Armacao left standing. It is a low, square fortification with a small chapel inside and a courtyard open to the sea.
The interior is occasionally open for cultural events but the building's main value is as a viewpoint: walk around the outside for a panorama back along the curving beach and east toward the cliffs of Benagil. Sunset here is reliably good.