Why were castles not built after 16th century?

Castles had three main functions: They served as the area's garrison for soldiers and its defensive stronghold They were the residences of the area's leadership They were places of refuge A castle could also be the town's gathering place--if there was no war at the time the castle's owner might want to use the courtyard as a marketplace, or something like that Then they invented cannons that could punch through castle walls, and the castle designers responded by building artillery-proof castles. They weren't fun to live in, so the kings who lived in the castles quit building castles; they chose to build good forts for their soldiers, and manor houses for themselves.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.