These camps should remain; certainly not bulldozed. In many of the camps I have visited coachloads of German schoolchildren were being apprised of their recent past. Accordingly, knowledge of the Holocaust is a feature of virtually every German's psyche.
Auschwitz 1 and Birkenau are as important as Waterloo, and being within living memory, more significant.
For the sheer dimension of the horror, I also recommend a visit to Ravensbruck, Buchenwald, Sachsenhausen, Dora, Flossenburg, Natzweiler and Mauthausen. Even Dachau perhaps, though it is somewhat sterile now.
Then read: 'The Theory and Practice of Hell' by Eugen Kogon.