From this vantage point, the back of the #SpinnakerTower can be seen.

And here are a few more views of it from a a bit closer.

The tower is 170 m tall with three #ObservationDecks, the lowest of which is 100 m hight. I have to say that my wife was a little underwhelmed by the structure until, that is, we got up to the first #ObservationPlatform. A clue is that dark rectangle you can see on the underside.