which way is up

“It is impossible for the inhabitants of different worlds to walk or sit or stand on the same floor, because they have differing conceptions of what is horizontal and what is vertical...”- M.C. Escher ----

The Campanile (the bell tower) of the church of San Martino Vescovo on the Isle of Burano in Venice leans 1m 85 from vertical. When I first spotted it from the lagoon I thought the thing could topple at any moment. But when I imaged this pomegranate tree with the bell tower in the background, the tower appeared not to lean. Many tourists (from different parts of the world) photograph this tower and come away with different conceptions of horizontal and vertical. Sometimes the tower appears perfectly vertical and sometimes the tower is leaning.