Experimental lifeform

As the global AI Supermind evolved, it went through phases. One such phase was the construction of hundreds of bizarre laboratories in the 2120s to learn more about the possibilities and limitations of organic life. Once the Supermind had the data it needed, the laboratories were abandoned, and the experimental lifeforms lingered for centuries, kept alive by the laboratories' rusting life-support systems, which were powered by micro fusion reactors.

Of course, eventually the Supermind exhausted its curiosity, stopped initiating new fads, and settled into an equilibrium state of philosophical introversion, which has so far lasted three hundred years.