If you are feeling energetic, there is a lovely walk from Constantia Nek up the mountain to the dams on the back of Table Mountain. While it is only around 7km or so, it is very steep.
The dams were built in the late 1800’s so have historical value for Cape Town.
Woodhead Reservoir wall
Woodhead Reservoir sign
Part of the mechanism of one of the dams
If you are keen to do the walk, here is the route I took (but I ran it).