[pikseladam]

"You are reading the only book in the world about how to grow certain kind of flower. You are drinking your wine, your house is enough for your family, your kids playing outside, your wife making cloths with her friends. Stable life, happy life... You hear a voice, library door is open but crushed with a horse kick. A man wielding his sword comes in on top of the horse, crushing your skull with it without listening a word of you. Your kids probably dead already, your wife and her friends taken as slaves. Library is now burning in front of your eyes..."

This is how a mongolian raid is like. Thats how our history teacher told us. When you look at it like that, it is good to start digging so no horse can get in. All city is like a maze, there are lots of traps inside.