The Snake Lemma is a classical result in homological algebra that connects kernels and cokernels arising from a commutative diagram of algebraic structures with exact rows. From such a diagram, the lemma constructs a new exact sequence that reveals deep relationships between the underlying homomorphisms. In particular, it introduces a “connecting homomorphism” that links information lost in one part of a diagram to information appearing elsewhere. This result plays a central role in many areas of modern mathematics, including algebraic topology, module theory, and homological algebra, where it is used to construct long exact sequences and study the structure of algebraic objects. In this talk, we will introduce the necessary background on exact sequences, kernels, cokernels, and commutative diagrams before presenting the statement and intuition behind the Snake Lemma. We will outline the idea of the proof using diagram-chasing techniques and illustrate how the lemma creates a bridge between algebraic structures. Finally, we will discuss why mathematicians care about this result and briefly describe some contexts where it appears. Interestingly, the Snake Lemma has even appeared in popular culture the opening scene of the 1980 film “It’s My turn” features a mathematician presenting a proof of the lemma.
