Descriptive InformationSIGN "NO TRESPASSING". To left of entrance to iron span of. Sign which was ignored. Original caption: Park: HFNHP; NEGATIVE NO: NHF-3008_A&B; Subject: SIGN "NO TRESPASSING"; Location: to left of entrance to iron span of B&O railroad bridge going across Potomac to enter tunnel; Purpose: Sign which was ignored by Dundalk, Balto HS on 5/30/66 boys when they crossed the bridge to climb MdHgts; photographer and companions: Bud Dutton, NPS; DATE: 6/2/66.