Barreling along: 3D macrostructures (cylinder; see picture) have been assembled from single-layered graphene oxide and noble-metal nanocrystals (Au, Ag, Pd, Ir, Rh, Pt, etc.). Although the density of the cylinders is very low (ca. 0.03 g cm−3), they show excellent mechanical properties and have been utilized as a fixed-bed catalyst for the Heck reaction, which proceeded with nearly 100 % selectivity and conversion. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.