What network is Tezos on?

I'm curious to understand the technical underpinnings of Tezos. Could you elaborate on the network that Tezos operates on? Specifically, I'm interested in knowing if it's a fork of an existing blockchain, a completely new architecture, or something else entirely. Understanding the network foundation is crucial for assessing its scalability, security, and overall potential. So, what network does Tezos leverage to power its operations?