On 29 April 2025, Portugal released a set of 6 stamps commemorating “Coastal Castles and Fortresses”. The highest value of these stamps (€1.33) shows an image of Outão Lighthouse which is located in the port of Setúbal. The light is situated on an old fortress which has been converted to a hospital.

Thanks to Jaap Termes for alerting us to this issue.
See more lighthouse stamps from Portugal here