Which Are your favourite gardens/Parks in Hyderabad?

I like the OU botanical garden. Although it is nothing like a botanical garden, its peaceful, you don't have horny couples everywhere and open during the afternoons as well.

I often pass by this thing called 'Japanese Garden', have been seeing it since many years but never saw it open. Its always closed, whats the deal with that place? Its between Jubliee Hills check post and TDP office.