This image* from Wikipedia surprised me. The topside building is...you could say...the tip of the iceberg. The detectors span a huge area going over 2km deep. The predecessor AMANDA array was also down there.
reply*https://en.wikipedia.org/wiki/IceCube_Neutrino_Observatory#/...
Yes. It spans a cubic kilometer.
replyThe building is just for housing the data gathering and comms equipment and whatever maintenance and engineering stuff the array needs. I don’t think anybody physically works there regularly.