Westerlund 1 is the biggest and closest “super” star cluster to Earth. Data from Chandra and other telescopes is helping astronomers delve deeper into this galactic factory where stars are vigorously being produced. Observations from Chandra have uncovered thousands of individual stars pumping out X-ray emission into the cluster.
https://www.nasa.gov/image-detail/54735875999-125f41fdb7-o/