 Complete the following phrase:  On 2 January 1971, during an Old Firm match at Ibrox, Stein scored an equaliser in stoppage time to salvage a draw for Rangers after Celtic had taken the lead in the 89th minute. Minutes later after full-time, barriers on Stairway 13 at Ibrox gave way, causing a chain-reaction pileup of spectators that killed 66 and injured over 200 in what would be remembered as the 