
In the last decades old windmills have been restored and transformed into summer country houses, like this one located in southern Portugal (west coast).
As this post is an off-topic (nothing to do with Oeiras) I leave you with Falcão Azul (Blue Hawk), an helicopter company whose
site has some interesting aerial views of Lisbon and other parts of central and southern Portugal. Click on the engish version and it will automatically show you the five clips (options on the right).