Is Uniswap only on ETH?

I've been hearing a lot about Uniswap, but I'm still a bit unclear on its functionality. Could you clarify for me if Uniswap is exclusively limited to the Ethereum network? Or is there potential for it to operate on other blockchain platforms in the future? Also, I'm curious to know if Uniswap's popularity and usage are limited to certain regions or if it's a globally accessible platform? Finally, given its decentralized nature, how does Uniswap ensure the security of transactions and protect users from potential risks? Thank you for shedding some light on these questions for me.