  We prove the existence of gapped quantum Hamiltonians whose ground states
exhibit an infinite entanglement length, as opposed to their finite correlation
length. Using the concept of entanglement swapping, the localizable
entanglement is calculated exactly for valence bond and finitely correlated
states, and the existence of the so--called string-order parameter is
discussed. We also report on evidence that the ground state of an
antiferromagnetic chain can be used as a perfect quantum channel if local
measurements on the individual spins can be implemented.
