looks to me like your fans are not working or you may have a waterpump issue.
thermostats are designed fail safe, so its a rare day they fail closed causing over heat, they usually fail open so dont get warm enough, its safer.
investigate your fan resistor. as a 2 minute bodge job temp fix take the plug off the resistor and short out the two terminals in the plug. this should make the fan run straight into high speed moment any fan speed is triggered.
then to test this all works, fire her up and unplug the temp sender should make the fans run straight away as well.
if you carry on letting it get that hot for much longer I should give NASA a call and tell them to expect 4 cylinders headed their way!
1999 156 1.8TS Sport Pack 3
2001 166 3.0 V6 24V Super
2003 156 GTA 3.2 V6 24V
2005 156 1.9 JTDM-Jet Sport
2008 159 1.9 JTDM Lusso
1997 GTV 2.0TS Lusso
2001 147 1.6TS Lusso