Chiesa di San Pantalon

San Pantalon looks unremarkable from outside -- its brick facade was never finished with the marble cladding originally planned -- but its ceiling holds one of the largest painted canvases in the world, an illusionistic sky that appears to blow the roof wide open above the nave.

San Pantalon charges nothing to enter, which makes it unusual among Venice's major painted interiors and also makes it dependent on the donation box. A church that asks for nothing still has a ceiling of forty canvases to conserve.

It is a working parish first and an attraction second, and the difference shows: there are no barriers, no wardens and no marked route, so the responsibility for behaving well inside sits entirely with the visitor. Quiet, no flash, and not walking through a service are the whole of it.

The neighbourhood around it is residential and academic rather than touristic. Groups stopping in the small campo block a genuine thoroughfare between Santa Margherita and the Frari, and there is no room here to absorb them the way the larger squares can.

San Pantalon is free to enter and just a short walk from Campo Santa Margherita in Dorsoduro. Early morning or late afternoon light works best for viewing the ceiling, and a visit rarely takes more than 30 to 45 minutes.

The ceiling is lit by daylight through the nave windows and by very little else, so the visit depends almost entirely on the weather and the hour. A bright morning or a clear late afternoon shows Fumiani's sky as intended; an overcast winter afternoon reduces it to a brown blur.

The illusion is built for a specific viewpoint. Standing directly beneath the centre flattens it -- the painted architecture only lines up with the real walls from partway down the nave, nearer the entrance, which is where to stand before looking up.

Opening hours are short and split around a long midday closure, and as a parish church rather than a museum they are not rigorously kept. Late afternoon is the more reliable of the two windows.

Entry is free, which means no queue at any time of year -- the one church of this calibre in Venice where arriving in high season costs nothing but a walk.