Can email work without internet?

I'm curious to understand, can email truly function without the internet? It seems like such a fundamental aspect of email communication, but is it possible to send and receive messages in a digital format without relying on the vast network of interconnected computers that make up the internet? Or is the internet an indispensable component, enabling the seamless transmission of emails from one user to another? I'm eager to learn more about the intricacies of email communication and how it interacts with the technology that underpins our modern world.