wood timber stone etc
Castles are made out of cement and/or brick
Castle
you could also use straw and cocktail sticks for the houses and the bridge.
you should use it on a moat
Bricks
Cake.
they use candles.
hammer
You could build it or use Tale of Kingdoms or Castle Defenders mod
Go to the seashore and build a sand castle. Then try to build a water castle and/or an air castle. That should tell you everything you need to know to answer this question.
Yes, it was used to build stuff.
what matrials didthefirst americans use to build their home