Synthetic Aperture Radar (SAR) is an "imaging radar" and is a powerful geophysics research tool.  It operates in the microwave regions of the electromagnetic
spectrum , making it capable to observe planetary surface features without Sun light in all weather conditions, even under rainy or snowy conditions. The airborne and satellite - borne SAR platforms have evolved from NASA- JPL AIRSAR, ERS-1/2, JERS-1/2, RADARSAT-1/2 and TerraSAR-X to the new generation of multiple satellite constellations. This talk will focus on the observation of selected Earth's surface features such as active volcanoes, inter-tidal flats, and physical oceanographic features with Synthetic Aperture Radar (SAR). The fully polarimetric SAR systems will also be introduced.