The LMC is the largest satellite of our Galaxy and has a total mass roughly 1/6th that of the Milky Way. In this talk, I will review the multiple lines of evidence for the LMC being so massive and then focus on the substantial effect it has on our Galaxy. In particular, I will discuss its effect on stellar streams, the stellar halo, and orbits of satellites around the Milky Way. I will show some preliminary predictions of how the dark matter haloes of the Milky Way and LMC are tidally deforming in the presence of each other and how we can hope to measure this effect in the coming years.