How does Axelar work?

Could you elaborate on the workings of Axelar in a nutshell? I'm particularly interested in understanding its underlying principles and how it facilitates cross-chain communication and interoperability. Does it rely on a central hub or a decentralized network? How does it ensure secure and efficient transactions between different blockchains? I'd also appreciate any insights into its scalability and potential for widespread adoption in the crypto ecosystem. Thank you for taking the time to provide a concise yet comprehensive answer.