This is from Milky Way Scientists (a Facebook site you really should join) via Matthew Cobb:
Scientists at the New Zealand Marine Studies Centre placed glass shells into a hermit crab tank. The crabs soon moved into the glass shells and made themselves comfortable, allowing researchers to take these amazing photographs.
There's only one photo, but it's cool:
Hermit crabs must change their shells as they molt and grow; here's a video of the decisive moment when one moves house.