How stellar clusters form is a fundamental open question in modern astrophysics. Most young stars are observed in groups or clusters, still embedded in their natal molecular clouds. But, within 10 Myr, only about 10% of stars remain bound to their birth clusters. The vast majority of stars have already dispersed into the field, or are found in unbound stellar associations by this age. This raises the question: on what spatial scales do stars form co-evally? And for how long do the initial conditions, such as spatial configurations and kinematics preserve after stars de-couple from their natal gas? Using Gaia DR2 data, we have discovered a large scale (300 pc long), co-eval cigar-like structure that is compact in proper motions, and located about 400 pc from us. The relic filament is roughly 35 Myr old and connects four already known open star clusters and three newly discovered ones. The latest DR3 data, complemented with radial velocities, provide an even better and more precise picture of this structure. This allows us to see, almost frozen in time, an ensemble of young stellar clusters/groups just getting out of the original nascent filament. This is a unique event, picturing the status of young stars at the early stage of their life formed together co-evally on such an unexpectedly large spatial scale.