IKARI (OFF):“A cavern left behind by someone, who was not us.
Though eighty-nine percent of it is buried.”
FUYUTSUKI:“An underground cavern that was originally a neat spherical shape...”
Mr. Tines: Tell us it's a Forerunner artifact without telling us it's a Forerunner artifact.
UrsusArctos: It certainly seems a better way of going about it than having Cortana say "this tunnel is not a natural formation" when said tunnel is metallic, covered in electronics, and on a 10,000 kilometer Forerunner giant hula hoop/antisonuvabitch machine in space.
