On the opposite side of the centre and the largest part of the city, Havana has a peninsula with a viewpoint overlooking Havana, as well as a castle and a lighthouse. You can get there by a small ferry that runs regularly throughout the day and is super cheap (1 CUP).
At the viewpoint there is a Jesus statue facing Havana having a, although the view is slightly limited by bushes at the bottom, really nice view overlooking entire Havana – or at least the centre. The castle itself is nothing special, but the view from next to it – where I watched the sunset – is really pretty. The lighthouse as well is pretty cool. I met somebody at the castle who took me to the top of the lighthouse for free. Since I had never seen a lighthouse so close up and from the inside, it was really cool 😀 😊 And the view of Havana at night from up there… very, very beautiful 😊

Go or not? Yes, I think it’s worth it. Since you have to take the ferry to get there etc. you should check out the centre and the tourist area first, but I personally think the trip is worth it.