Puzzled by a roof in London

I know I took this shot in London in 2016 but for the life of me I cannot recall where! I think it was in Greenwich, can anyone enlighten me?

PS have you noticed all my roofs to date have been made out of glass. I spotted this when I was collating them ready for this month’s challenge. Must be something about glass roofs. I think this is my last one this week, albeit tomorrow’s is almost glass!