Laughing, Megatron aburptly (if gently) pushed Orion through the seemingly solid wall, and the corridor beyond was softly lit by directionless, sourceless golden light.

"Quite a few things down there make no sense, when you get past the ruined layers of older settlements," he said as he followed Orion through, looking around the curving corridor, part of it made up by what seemed to be tightly braided cables, the rest by interlocking hexagonal plates with subtle carvings along each edge.

"This," Megatron said and reached out a hand, laying it against the wall, "as far as I can tell, has never been at the surface, compared to the ruins outside."