What is The Sandbox?

The Sandbox is a "pocket galaxy." A self-contained galaxy that was already filled with habitable planets and with functional ecosystems, flora and fauna. 

Over the past 400+ years, a mysterious force has kidnapped fleets of colonist ships direct from other galaxies and dumped them here. No explanation.

No other galaxies are visible from The Sandbox. Which makes it impossible for any of the Races to navigate back to their home galaxies. There is no clue as to how these various Races were brought here. Or why. 

The various Races must get along. And for the moment, there's enough space for everyone. And enough resources.

But that doesn't mean there's peace...