Definition: Generate a question which can yield the answer mentioned in the input. Generated question must be answered by the answer provided in input, without using any extra knowledge.
Input: Context : The Nelson Mandela 90th Birthday Tribute was held in Hyde Park, London on 27 June 2008 to commemorate Nelson Mandela's ninetieth birthday (18 July).
Answer : 27 June 2008
Output:
The date of Nelson Mandela 90th Birthday Tribute was what?