The Huge Large Quasar Group, is a possible structure or pseudo-structure of 74 quasars, referred to as a large quasar group, that measures about 4 billion light-years across. At its discovery, it was identified as the largest and the most massive known structure in the observable universe, though it has been superseded by the Hercules–Corona Borealis Great Wall at 10 billion light-years. Its existence has been disputed.