Prior to visiting the recompression chambers themselves, we had an introductory lecture about how recompression therapy and high pressure oxygen treatment is used in medical treatment - there are a surprising number of applications apart from curing divers with decompression illness. We then visited and inspected the chambers and the first group entered for their dive.
On the way down, the temperature rose to over 35°C, the full balloons shrivelled, the empty water bottle and the tennis ball were crushed completely flat, and the material of a thick neoprene diving hood became as thin as an elastic band. Below 25m our voices went all higher pitched and nasal, while at the maximum depth the nitrogen narcosis made us feel light headed and the bones in all my joints clicked a bit as they settled into a new position. 
(There's a "law" about nitrogen narcosis called "Martini's Law", which states that for each 5m below 30m, it feels like you had just drunk another dry martini - so we had had 4 doubles!). Then we did a cognitive test which involved recognising letters in a block of text and circling the correct ones. Everyone did this OK - so this is evidently a task which is not affected by the narcosis. However, it was noticed that noone could understand the written instructions (which were very clear) until told verbally what they were supposed to be doing.On the way up, balloons we had blown up at 50m got huge and burst and the dropping pressure caused a fog in the chamber and it became really cold. The tennis ball, water bottle and neoprene hood regained their normal shapes, and our sensations of disorientation vanished. Those tough guys who didn't put jumpers on or wrap up in blankets then had to endure 15 mintues of decompression at 6 and 3 metres, and ended up with itchy skin - which was actually a minor skin bend, said the technician in charge, because they had got cold and the circulation to the skin had stopped. This eased after 15 minutes on the surface and we watched as the second group played the same games in their turn.
Sandwiches and drinks preceded a closing lecture and then it was a 2 hour trip back home. This was a very worthwhile experience and I hope we can do it again with the next group who qualify as Sports Divers in due course.