I have and the worst sink estate in London is nothing like as bad as Havana, at least not in terms of the physical infrastructure. Crime is probably worse in London.
And yes I am aware that as a tourist those are the bits I was allowed to see; I'll wager the "real" Cuba is far worse.
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You went on a tourists' visit of poverty. Try doing the same in London, and let's see how you do there, bruv.