Gabriela - you wouldn't like this...!
So - what's going on in this photo then...? This is what Ibusuki is famous for: hot sand baths (sunamushi onsen). You get buried in the hot volcanic sand, which has a sauna-like effect and is supposed to be very beneficial for your health. The recommendation is that you stay buried for 10 to 15 minutes maximum; my wife only informed me of this after I nearly fainted after taking my bath, having been buried for about 25 minutes.
Also - apparently the view when you visit the baths isn't always that of a cattle shed. This was a temporary enclosure, as the usual beach-side onsen area was being renovated.
I found a very good account of visiting the sunamushi onsen here: http://notesofnomads.com/ibusuki-sand-baths/
I apologise in advance if I'm tardy with commenting on your blogs or returning comments during the week... I will get to you though!