Cat on a warm tiled roof

I've been wanting to take a picture of this building for quite a while as it's on my way home. I'm always wondering, when I see round walls/roofs like this, how it must be like inside. This room looks particularly small, so I'm guessing they can't fit a lot of equipment, unless they have special round pieces of furniture!

(If you look in large, you'll notice a cat on the left of the chimney. He was calmly walking the length of the roof, as cats do, but I was afraid he would fall!)