 Synthetic Aperture Radar Interferometry, NSAR, is a powerful tool for measuring surface deformations caused by natural and human activities. It can measure three-dimensional deformations and track them over time using multiple satellites and different frequencies. Recent advances have made it possible to combine data from multiple satellites and frequencies to create more accurate measurements. These developments are particularly useful for studying geological processes such as volcanoes, landslides, and earthquakes. This article was authored by Antonio Pepe and Fabiana Kahlo.