Throughout history many different cultures across the world have concluded that the heart is the most important organ in the body.
Often thinking the heart was more akin to a brain with blood vessels sending messages around the body. And although this is wrong, Its easy to see where the fascination with this organ in particular comes from, its the Centre of an incredibly complicated network of tubes meandering through almost every part of the body and is absolutely crucial for almost every function in the body.
So How did such a complex mechanism evolve with multiple parts working together evolve and how did animals get by without something so important for life, before the evolution of the heart?