cover 1917 XU5 to Brazil, bearing 25f. tied by "BUDAPEST/4" c.d.s. showing "Tauchbootbrief" in manuscript adjacent, also framed Hungarian censor cachet and "BREMEN 1/T.B./D.O.R." (Tauchboot Deutsche Ozean-Reederei) c.d.s. (30.1); reverse with "OPENED UNDER MARTIAL LAW" label and "BREMEN/1D" arrival c.d.s. (23.1). The letter was returned to sender as the submarine service had been suspended. Photo