Superclusters form massive structures of galaxies , called `` filaments '' , `` supercluster complexes '' , `` walls '' or `` sheets '' , that may span between several hundred million light-years to 10 billion light-years , covering more than 5 % of the observable universe .
Superclusters themselves form even larger structures , called `` filaments '' , `` complexes '' , `` walls '' or `` sheets '' , like the Great Wall . These may span between several hundred million light-years to 10 billion light-years , and cover more than 5 % of the observable universe .