Since 1972, the joint NASA/U.S. Geological Survey Landsat satellites have continuously observed Earth, accumulating the most complete archive in the world of temporally and spatially remote sensing data. This allows us to witness time change analysis, global phenomenon, natural hazards, urban/human changes, and many other studies waiting for discovery. Anya Hartpence, a volunteer NASA Solar System Ambassador, will discuss this ambitious project and how the data acquired in the past 50 years benefits civilization - past, present, and future.