Butterfly Sensation was the name of the walk-in exhibition at the NHM.  I think I must have a butterfly-friendly smell or something because there was always one perched on my arm/head/shoulder bag !!  Anyway, we had a great day in London - and if you ever get to the Museum you must pay a visit to the Cocoon - an amazing state-of-the-art building where the research scientists work.  There are loads of exhibits and lots of information.  And of course we paid our regular visit to the dinosaurs!!