São João das Maias Fort

São João das Maias Fort is part of the coastal defense constructions that were built after Restoration of Portuguese Independence around the year 1644.
The Fort location was considered to be of high importance to prevent attacks from the Atlantic Ocean and to prevent the entrance in Lisboa through the River Tagus.
This was one of the fortress that was kept operational during many years, having been definitely abandoned as a defence element of the coast around the year 1870.
Nowadays it is property of the Portuguese Armed Forces.