"It was set up because of the tragedy that was Chernobyl."
Should there be at Chernobyl?
The rather grandiloquent form of words 'the X that was/is Y' is quite common in a certain kind of journalism. It gives the sentence an aura of "poeticness" by allowing the writer to introduce a value-judgement and then assign something to it - e.g 'the minefield that is married life'.
b