I was not sure exactly where to put this but it involves images so I thought it was no too inappropriate here. I was reading the Feynman Lectures Vol.1 and he says that Helium, although not solid at absolute zero normally, can be so in high pressures. I then googled this for images but none turned up. Why is this? Can it only be done in lab conditions? Is it only done in small amounts? Thanks, it is just a light query but I am interested to know why.