The point at which all other horizontally drawn lines must vanish - it gives perspective, depth. Like history, it depends on your point of view. Take the Sacre Coeur, built in expiation of the crimes of the communards on Martyr's Mount or the Mount of Mars or to give thanks after the Prussian Wars - the Wedding Cake, an icing sugar, Romano Byzantine treat or a carbuncle on the face of Paris? It rises like a great and holy ghost - self bleaching - overseeing the city's polluted dreams and it offers an unparalleled perspective on the city - 30 miles to any vanishing point you like.
Having performed the penance of 257 steps up to the mount, a spiral circlet of walls will lead you into a circular gallery inside the dome, vast and high. And the view? You must go and see it for yourself.
There are 352 steps twixt crypt and dome. How do I know? I counted every claustrophobic one - creating an oasis of numbers in my head, a numeric safety net - until I'd reached the very top.
Then with knees of jelly, I crawled towards the door and gulped air. Reluctantly I stood up, whiter than the dome itself, against its curvature with eyes shut tight, then I sank and crawled back along the floor and descended those stairs on my bottom, counting each one again and the tears I shed were not for the martyred dead.
You might think it's a pity I never saw the view. From my perspective though, it was a triumph.