Why is "Death in Venice" set in Venice?

One of the central themes of this excellent short story is
the way in which pursuing eroticism, as symbolised in the figure of Tadzio, and
relinquishing restraint and reason, can lead to death. Note how von Aschenbach for
example deliberately chooses to stay in the city in spite of the cholare epidemic and
the threat of death. Throughout the story, a relationship between eroticism and death is
created, and this is supported by the setting. Venice is a city that is famous for its
sensuous symbolism, yet it is also a city that is well known to be decaying and dying
year by year. Note how the text itself connects this too ideas in the city of
Venice:

Is
there anyone but must repress a secret thrill, on arriving in Venice for the first
time--or returning thither after long absence--and stepping into a Venetian gondola?
That singular conveyance, come down unchanged from ballad times, black as nothing else
on earth except a coffin--what pictures it calls up of lawless, silent adventures in the
plashing night; or even more, what visions of death itself, the bier and solemn rites
and last soundless
voyage!

Note how this quote
combines the excitement of probably illicit sexual adventuring with death in the
imagination of the protagonist. Thus setting the story in the city of Venice helps to
emphasise the important thematic relationship between sex and
death.