A Sudoeste do Cabo a Roca e sensivelmente a meio da alta falésia, erguem-se as ruínas do fortim seiscentista mandado erigir por D. João IV, integrado no sistema defensivo de Lisboa. Do monumento subsiste hoje parte do troço muralhado e da abóbada do paiol. Foi abandonado, por já não se justificar, no século XIX..
The ruins of this 17th century fort, which was commissioned by King João IV, as part of Lisbon’s defence system, lie approximately halfway up the steep cliffs to the southwest of Cabo da Roca. The present day remains of this monument include a part of its walled section and the dome of its gunpowder magazine. Having outlived its usefulness the fort was abandoned in the 19th century.