The Mars Perseverance rover has been collecting samples from the Martian surface, specifically in the Jezero crater in the hope that one day these samples will be returned to Earth. The crater, marked by lavas, ancient rocks, and sediments deposited by water, was chosen to help answer questions about the planet’s geological history, its ancient magnetism, to whether or not life has or ever had existed on the planet and more. This special collection for PNAS brings together the reasons bringing samples back to Earth is critical, with contributions from EAPS faculty members Ben Weiss and Tanja Bosak.