Venice is no ordinary city, and neither is its cemetery.
Until the early 19th century, Venetians usually buried their dead under paving stones within the central city, not a salutary practice, particularly in times of pestilence.
So the Austrian occupation decreed in 1837 that San Michele would be the only possible burial ground for most Venetians.
Since San Michele is a very small island, however, it is usually only a temporary resting place.