Comments of chapter undefined of IN [ASOIAF/GOT] - Like Arthur Pendragon and all the Skills and Power

I think one of the reasons Harrenhal was never rebuilt or destroyed. Apart from that it would be extremely expensive and not worth it. It is because Aegon and subsequent Targaryen Kings forbade its reconstruction or destruction because it is a symbol of Targaryen power. The largest castle ever built, melted by the power of the dragons.