Is USDT real or fake?

I've heard a lot about USDT recently, but I'm not sure if it's legitimate or not. Could you please explain what USDT is and whether it's a real cryptocurrency or a fake one? I'm particularly concerned about its reliability and whether it's backed by any assets. Additionally, how does it differ from other stablecoins, and what are the potential risks associated with investing in USDT? Thank you for your time and assistance.