Since we have a Big organ thread, I thought it fun to add a Small organ thread (because small organs are also fun, and some of them have been as influential, and are as important historically, as their grander counterparts). I'm slightly undermined because one of my candidates is already in Fsharpminor's excellent link to mixtuur.com, namely the organ at Sion, Switzerland. It's often claimed as the oldest playable organ in the world, but Rysum in Germany is sometimes claimed as earlier.
And here is Sion:
No list of interesting small organs would be complete without Frederiksborg castle in Denmark:
This is an odd one though, as it's actually a 2-manual instrument with pedals and a surprising amount of tone colours for its not-enormous case; as such, different performers bring out wildly different flavours from it. The one I've posted conjures images of Drake off to capture the Spanish galleon, but there are plenty of recordings on YouTube where it sounds far more modern!
As a bit of a weird one, here is a randomly selected old Italian positive organ, genuinely very small. And yet it doesn't sound small
It has character and more presence than many of its bigger cousins. I think it makes an interesting comparison with the convenient but generic, muffled, nondescript gedackt-in-a-box organs that one meets so often.
There are lots of interesting small organs around. Anyone else got any claimants?