Ricasoli Fort is a large fortification on the island of Malta. The fort was built by the Knights of Malta between 1670 and 1693.
Movie Locations, Military - Historic - Forts and Batteries
The vast 'Roman' sets of the movie Gladiator (with CGI additions) were constructed on the massive remains of Fort Ricasoli on Malta, later used for the filming of Troy. [movie-locations.com]
Links: en.wikipedia.org, gameofthrones.wikia.com