A knot that ties itself! The entanglement of six ligands coordinated to three PdII ions results in the quantitative formation of a walnut-shaped supramolecular cage. Each of the two hemispheres resembles a trefoil knot. The solution-state structure was elucidated using a combination of NMR experiments and calculated model structures. The final structure was selected from several models by topological analyses and encapsulation of chiral camphorsulfonate ions.