What is Polkadot built on?

I'm quite fascinated by the concept of Polkadot and its potential in the blockchain industry. Could you please elaborate on what Polkadot is actually built on? I've heard mentions of its unique architecture and interoperability features, but I'd like to understand more about the technological foundation that supports it. Is it based on a specific programming language or framework? How does it ensure scalability and security? And what are the key components that contribute to its overall functionality? I'm keen to gain a deeper understanding of this innovative project.