Barbican

I was wondering what the Barbican is, even it was obviously an estate.
It was good to take part in the Barbican tour which was one part of the Le Corbusier Exhibition.
The presenter who is studying modern architectural history(?) explained the buildings comparing with Le Corbusier's 5 points of architecture.

The approaching to the Water Garden is impressive. It looks like getting into the water rather than just seeing it. If I mention the Water temple by Ando Tadao, is it exaggerated?