This small display (there's a little more to it than pictured) tucked into a corner was one of the most interesting things in the museum besides the architecture and the BGS - frankly most of it didn't interest me that much, not that some of the collections and displays aren't impressive.
It's about historic expeditions in Antarctica, and includes some rocks from the mountains there, which when collected confirmed what had been uncertain beforehand - that it was an actual continent with alpine-like bedrock and not just a big piece of ice.
This display looks like it's from the 60's. All of the modern stuff they replaced this kind of stuff with is bland and uninteresting...
And I have to say the photo I'm shamelessly attempting to profit off of here (in page views) is absolutely incredible in person - my camera didn't really capture it very well but it's a masterpiece of Antarctic photography in my opinion. The caption is 'Captain Scott's ship "Terra Nova" at the ice foot off Ross I. South Victoria Land, in January 1911', in a very nice font.
The photo is in the flickr commons here from the New Zealand National Library.