We describe observations of multisteps, up to n = 5 steps high, that form on Pt(1 1 1) at temperatures above 1400 K. Using step fluctuation spectroscopy, we determine the multistep stiffnesses, beta(n), and so estimate their line free energies, assumed isotropic. Measurements of mode relaxation times tau(nq), for modes of wavevector q, reveal that beta(n)tau(nq)/n(2) depends only weakly on step height, n, in agreement with capillary theory. From the measured energies, we infer that multisteps have large free energies of internal motion, such that the net thermal free energy, including capillary modes, undergoes only small changes when steps merge. (C) 2003 Elsevier B.V. All rights reserved.