As you can't see, the Citadel in this room is Absent.
Nevertheless, the immense length of the Chain it was made for can be seen!

Alex's Chain Fortress

chakhatic's Rare Citadel of the Chain of Creation

Donut's Loud Temple of the Chain of Cold

folk's Chain Citadel

starryrainz's Dark Atrium of the Nameless Chain

thunderzizi's House of the Prismatic Chain of Adequate Life

shmewtep's House of the Chain

BlueTinge's Common Locus of the Chain

tinytoes's Studio of the Chain of Victory

limikun's Cabin of the Hollow Chain of Power

wit's Prismatic Workshop of the Radiant Chain

Hypercube34's Atrium of the Chain of Light