Photos and reminiscences of life the 1950s, part of the decade-by-decade series that vividly documents the Crescent City's history. Remember when Mardi Gras was cancelled in 1951 in tribute to the men fighting the Korean War? Surely you were there for Elvis Presley's visit to the Municipal Auditorium in 1956, and you must recall the first time you crossed the brand-new Greater New Orleans Br…