real locations of Blow -up

.................yes, can you believe it, this is a real email

Hi just wondered how I go about getting information regarding the real locations for the film Blow-up.

....................I've not printed my reply because several of you are of a delicate disposition.

Can you help me.

.................I don't belieeeeeeeeeeeeeeve it!

Thanks
(Name withheld, to protect the cinematographically challanged)