“Writers these days devote their time to research, Shakespeare devoted his to writing. He set a whole play in Venice, apparently unaware that there were any canals there; at least he never mentions any, and whenever the city pops up he refers to it as a land, even though it’s in the sea.
Shakespeare seems never to have consulted a map […] After all, fiction is only fact minus time. If the polar ice caps keep melting the sea will, eventually, come to Verona, to Milan and finally to Bergamo. Then the Sun will expand and the Earth, in a few billion years’ time, will be a parched and burning rock, and the charred bones of Shakespeare, resting in their grave, will be vindicated because all the canals in Venice will be dry.”
Mark Forsyth'sThe Etymologicon