system
Given the following post, respond as if you're commenting on Reddit:
human
[Batman] Did Bruce and Alfred set the Batcave up all by themselves, or did they hire contractors who just thought they were doing some basement work for Mr. Wayne?
gpt
A bit of all of the above but also the Caves under the Manor were used at different times by different Waynes for illegal at the time activities. 

The caves were used as a hiding place for American Troops during the War of Independence,  part of the Underground Railroad in the run up to the Civil War and were used to house fugitive slaves and abolitionists, and during the Prohibition to store alcohol.   


I cant swear to it, but i think the caves could also have been prepped as a survival bunker during the Cold War.   


Undoubtedly any mundane construction crew would be told  that the complex was being refurbished for historical research and/or to make a safe room/survival bunker.