A drive with no purpose - but where?

Found myself with time to kill today and felt like going for a drive. I had no destination in my mind, no errands to run or anything in particular to do. As a result I couldn’t figure out where to go and as a relatively new driver, I don’t like driving somewhere random or unknown without GPS (which defeats the purpose of a random drive).

Are there any destinations you recommend for when you just need to clear your mind or just to enjoy driving in and around Sydney?

UPDATE. Thank you for all the awesome responses. I’m in Northwest Sydney so many of these are doable. I’m going to read through it all in detail this evening when I get home from work - especially love the Sheps Mound suggestion to watch airplanes!