Stellar streams, the tidal remnants of accreted globular clusters and dwarf galaxies, are uniquely powerful tools for studying the Milky Way. In particular, they allow for strong constraints on the local distribution of dark matter, and they provide insight into how our Galaxy has evolved over time. However, addressing these essential questions requires a large, well-observed sample of stellar streams with full 6D phase-space measurements. I will present the first population of systematically-observed 6D stellar streams, including their discovery in the Dark Energy Survey, and the measurement of their proper motions and radial velocities with Gaia DR2 and the Southern Stellar Stream Spectroscopic Survey (S5). In addition, I will present constraints on the mass of the Milky Way’s largest satellite, the Large Magellanic Cloud, and discuss future plans for using these 6D streams to learn about dark matter and galaxy formation in the Local Universe.