This is the Cathedra Petri in St. Peter's Basilica, directly behind Bernini's baldachin. It was built to house St. Peter's wooden throne, which Bernini enclosed in a typically massive bronze sculpture. The photo is (surprise!) a panorama stitched together to provide a good view of both the floor and ceiling.
That may be the most Italian thing ever.
That's a big space - tough to photograph!
Beautiful subject matter, & the wish to show it in its full glory is understandable, but it makes me feel the walls closing in.