Circumstellar disk of dust and gas are signposts for giant planets. In young systems (typically 1Myr old), giant planets carve out gaps and trigger density waves creating large scale structures that can be seen in sub-mm images taken by, e.g. ALMA. In adolescent systems (1 Myr to 1 Gyr), second generation dust disks are generated by collisional cascades between parent planetesimals under the gravitational influence of giants planets. Our team is leading observing campaigns using ground-based and space-based observatories to image and characterize these young and adolescent giant planets. Our goal is to understand how they form and how they shape the fate of planetary systems.