I may be wrong but I feel thick stone walls are a bit like having large buckets of water in a greenhouse: They regulate temperature, whereas modern insulated walls don't because they are indeed just very good insulators.
As for double or triple glazed windows, they are good at keeping the heat in but in my experience they are not that good at keeping the heat out: sunlight gets in and heats up surfaces, the whole room warms up, and then the heat is trapped.
A traditional way to try to keep cool in Southern Europe is to open the windows to create airflow while closing the shutters to keep sunlight and heat out. Now, of course this makes rooms quite shady. Villages completely quiet with shutters closed during 'siesta' are famous to the point of stereotype but that's a real adaptation: Stay cool and avoid efforts during the hottest part of the day.
As for double or triple glazed windows, they are good at keeping the heat in but in my experience they are not that good at keeping the heat out: sunlight gets in and heats up surfaces, the whole room warms up, and then the heat is trapped.
A traditional way to try to keep cool in Southern Europe is to open the windows to create airflow while closing the shutters to keep sunlight and heat out. Now, of course this makes rooms quite shady. Villages completely quiet with shutters closed during 'siesta' are famous to the point of stereotype but that's a real adaptation: Stay cool and avoid efforts during the hottest part of the day.