As someone who visited Wolfschanze Hitler's secret hideout in Poland, (where assasination attempt take place), I can assure you, you don't need to hide a compou

As someone who visited Wolfschanze Hitler's secret hideout in Poland, (where assasination attempt take place), I can assure you, you don't need to hide a compound under ground, it can be perfectly concealed on the ground in forest, if you really want it to stay invisible.