In Sao Pedro do Estoril there is the preserved spotlight used to light ships entering Lisbon harbor, canons further up would fire on the ships.
The canons have been abandoned but you can see the spotlight.
I have a photo of it in my trip report if you want to check in with, it's a long report scroll to post 31.
https://www.fodors.com/community/europe/extended-trip-to-portugal-1711933/page2/
Regarding spies there's a James Bond connection to Hotel Monte Estoril but also closer to Vermont.
In Whitby,Ontario, the author of James Bond , Ian Fleming attended Camp X ( yes that was the real code name) that was set up and run Sir William Stephenson - a man called Intrepid ( code name), the real life inspiration for the James Bond character.
I've visited the actual site ( at the south end of today's Oshawa airport), but unfortunately the buildings were completely destroyed, instead there's a small tank museum run by volunteers.
Elsewhere in Withby there's a plaque and a statue of the man called Intrepid.