what's the workload of a pro training session?
 

when they go out on a 5 hour ride every day, what do they do?? to they do 2 minutes intervals at 95% max for the whole time or such exercices? are they able to hold on for such a long period and to do it over again the next day? I understand they still have recovery rides like us, but if they average 20-30 hrs per week on the bike, their recovery rides must be at least 3hrs I guess...

No, 5 hour rides are most likely endurance. They're at 5% below up to probably no more than 5% above their LT on that ride. Maybe some rolling hill intervals at 90% effort.

The 2-minute intervals would fall on a shorter day like a 2-3 hour ride. Longer intervals and hills on a 3-4 hour ride. Hillclimbs on a 3-4 hour ride. Recovery day would be 2-3 hour ride also, but at 15-25% below LT.

It depends on the rider and style. I would guess a tour rider trains alot differently than a sprint or track rider

Yeah, a TDF rider probably does two of those 5-hour 120-mile rides a week. Track sprinters hardly ever ride more than a 2-hour ride. And spend a tonne of time in the gym doing weights and doing high-RPM spins on the trainers.. :)