Something must have fscked up big time to take down Visa payment all over Europe
I seem to recall that Visa used to use IBM big iron running TFP - I wonder if they still do? Because it's pretty difficult to think of a harware failure that'll take down a properly-running IBM mainframe..
(Other than complete cooler failure of course. Which is why you have multiple coolers. The only other thing I can think of is a power outage closely followed by the standby generator(s) failing.)
 Plenty of software failures though. *Cough* Allegedly.