Gallery 1: The Making of Caligula
The Tiberius Grotto Set. This was built outside, in a rectangular structure, commencing in the Spring of 1976. In the picture above, you can see the stars of the night sky above the set! At one end of this set was Tiberius' "Harum of the Monsters", and at the other end, the rock where Tiberius' taste tester died on a deadly drink meant for Caligula. The picture below shows the "Rock"
At the end of the filming of these "Capri" scenes, this set was torn down in the middle of September '76, and the "Stadium" sets were immediatly built in it's place. That's why none of the "Capri"  sets show up in "Messalina! Messalina!", because they were already long gone! The Capri interiors (Phallic Slope, Torture Chamber, Tiberius' Pool & Nerva's Bedchamber) may have been also replaced by the "Imperial Bordello Vessel". The 2 pictures below show the "Stadium" sets. These sets were torn down after the filming of "Messalina! Messalina! in July of  1977. The only thing that was saved was Caligula's bed, which Bob Guccione put in his New York Apartment!
The Stadium set. This impressive set was very effectively used in the movie to be made to look bigger. In the picture below you can see the Killing Machine blades being prepared. Also, in the dirt you will see 8 lines from left to right. These are actually rails inbedded in the dirt for the Killing Machine to move on!
Above, John Steiner goes to his dressing room. Below, Roman extras warm up between takes. Above left, three Matronly Roman extras await thier cues. To the left, an Artisan prepares one of the artificial heads used in the film's graphic beheading scenes. 
Above, workmen finalizing the killing machine, to the left, a hermaphrodite is fitted with a artificial phallus for Tiberius' orgy scene. Below, a production crew member uses an umbrella to shield the head of Guido Mannari (Macro) from the falling rain. This was taken in December 1976.
Chef Guiseppe Maffioli prepares a stunning orgiastic creation for the wedding banquet scene.
On to Gallery 2
Early into the shooting, August 1976. Peter O'Toole, Malcolm McDowell, and Guido Mannari get some final touches before the cameras roll. Tinto Brass gives some pointers from the script, adapted from Gore Vidal's original script by Masolino D'Amico, Tinto Brass and Malcolm McDowell.