Is sandbox on Ethereum or polygon?

Could you please clarify whether Sandbox operates on the Ethereum network or the Polygon network? I'm trying to understand the blockchain infrastructure underlying this platform and its functionalities. Could you provide some insight into the advantages or disadvantages of choosing one blockchain over the other for Sandbox? Additionally, I'm curious to know if Sandbox has any plans to expand its operations to other blockchains in the future. Thank you for your assistance in clarifying this matter.