Does anyone here know if most European cities don't have AC on their
underground train system. or is it just London?

IMX, a good proportion do not, except the very newest systems which
were built with it in mind. However, many systems are cooler than
London - probably because they normally have wider tunnels and larger,
better-ventilated stations.


I've just come back from Prague and the metro there feels like its
air-conditioned. Not sure when that one was built. The very recent Athens
metro has aircon