What is the Special VFR rule?

Can you please elaborate on the Special Visual Flight Rules (Special VFR) rule? I understand it's a set of regulations governing the use of visual flight rules in certain circumstances, but I'm curious about the specific scenarios in which it applies and the procedures pilots must follow to operate under these rules. Additionally, I'd like to know if there are any restrictions or limitations that come with flying under Special VFR. Thank you for your clarification.