We have designed, developed, and deployed the world's first ultra-dense space division-multiplexing multicore fiber link in a conduit of a metro network. In a 10-mm-diameter fiber optic-cable, 288 4-core multicore fibers are arranged in 24 200-µm spiderweb collapsible ribbons. The multicore fibers are fusion-spliced to 576 fanout devices which provide conventional single-core interfaces at patch panels at both ends of the link.