Our heroes have discovered 2 secret underground ways in the school that lead to the factory. It became their H.Q., but it's also the only way to Lyoko. In the 1st basement is the computer lab, which allows them to go to Lyoko. In the 2nd basement is the Scanner Room where our heroes are virtualized to Lyoko through big tubes. Deep under, in the 3rd basement is the Supercomputer controlling Lyoko.