Boulder Hill is the
headquarters of
M.A.S.K. It is a gas station at the base of a hill in disguise! In the
cartoon, it was a complex where they could park their vehicles and put on their masks in that ascending, rotating caroussel round table.
In the toyline however, it was simply a gas station where the gas pump stations could revolve and transform into laser shooting stations! There was also a boulder that covered the top of the hill that could be taken off so a seat with a gun could pop out. Under the hill was also a place where you could park the vehicles you had (I had Matt Trakker's Thunderbird).