In his REMEMBERING ORSON WELLES, Gore Vidal claims not to have seen F FOR FAKE, but a few years after FAKE was released, he wrote and hosted a superb essay-like film of his own called VIDAL IN VENICE. It deals with the history of Venice, but with many wonderful and witty digressions that reminded me a bit of Welles's film. It also illuminates some of the background for several Welles projects set in Venice, such as OTHELLO and THE MERCHANT OF VENICE. Just goes to show that great minds think alike.
Here is part 1 (of 12) on Youtube: