Montepulciano's cathedral sits on the southern side of Piazza Grande. Construction was completed in 1630, although its façade is unfinished, and very plain in comparison to the stunning marble facades of the cathedrals in nearby Siena and Florence.
The inside is thankfully more interesting, with a very impressive altarpiece which was created in 1401. It is painted on wood and decorated with real gold.
I particularly liked the ray of sunlight that streamed in through a window on the ceiling, creating a circle of light on the floor, making for an interesting, albeit a little bit blurry, photo.