NHM: Square Spiral Staircase

More effective in large ("L").

Eee, a new satisfying staircase! I bet there are still several for me to discover yet... I was actually shown this one so I can't claim to have discovered it. I also felt rather pressurised as I was being shown an alternative route out of the museum (avoiding the bottleneck that is the Birds Gallery...) and didn't know how long I could loiter without the other member of staff losing patience.

Anyway, I now know where this is, so will revisit it when I've more time to explore its angles, and also when the light is less contrasty.