The Barbican

This was great and the photos were good too!

I have a similar sort of fascination with a structure closer to me: Habitat 67 in Montreal. I have at various points considered buying a unit there but practicality prevents me from doing so each time. I don't know how long I'll resist.

https://en.wikipedia.org/wiki/Habitat_67

I visited outside it twice but they are very strict with protecting the privacy of the residents, so you aren't allowed in. I could only take some photos from street level outside.