Precursor Orbital Arch

Orbital arches or orbital ribbons were a type of orbital construction built by the Precursors. Like all neural physics technology, they were invulnerable to most weaponry available to the Forerunners, save for the Halos. On Charum Hakkor, one of the worlds to contain orbital arches, prehistoric humans built cities onto the structures, described by Bornstellar Makes Eternal Lasting as resembling "ivy growing on great trees".