All the old residences and monuments had extremely thick walls. The Kashempur residence had walls that were 700 mm thick and the takht mahal had walls that were 3 meters thick!

 

Thick walls can help keep interiors cool due to their high thermal mass, which enables them to absorb, store, and slowly release heat.

During the day, when the external temperature rises, the thick walls absorb the heat from the surroundings. However, due to their insulating properties, they do not transfer this heat to the interior immediately. Instead, they gradually release the stored heat back into the interior, creating a more stable and comfortable indoor temperature.

During the night, when the external temperature drops, the thick walls slowly release heat to keep the interiors warm.