Why are there giant concrete tunnels in the desert?

The Physics Girl team visited LIGO once again. This place is Dianna's obsession.
If you liked this video check out these:
I Visited the First Gravitational Wave Detector! LIGO | STELLAR
https://www.youtube.com/watch?v=jtp71NT0GNg&
Why aren't plants black? :herb:
https://www.youtube.com/watch?v=3BRP
link
gravity