Freyr stared out of the transparent side of the sphere as they plumbed the depths of the tower. Nearer to the spire’s base, the buildings became bigger and more communal, with more elaborate carvings. Freyr remembered reading that these structures were far older - the stratification of the tower had only emerged in the final thousand years this species was around.

Going significantly faster than normal, their sphere reached the bottom of the tower before slowly leveling out. They were no longer headed straight down, but rather through a large horizontal tunnel, with more alien structures all around them. Floor, walls and ceiling. The dual-rail system carefully tiptoed through the middle. 

Freyr gazed longingly at the sheer metal bulwarks that closed off causeways to unused parts of the ancient city. For a fleeting moment, escaping into the dark seemed like quite an attractive prospect. She coughed delicately. “They created the proto-harnesses which form the basis of today’s tech. The first colonists found three of them in the Cradle’s chamber, hundreds of years ago. Where they went is a subject of eternal debate.”

“Mama used to tell me they were still alive, hiding in the dead parts of their city.” Dr Apalkov growled. “And that they’d come and take me in my sleep if I didn't eat the food she cooked.”