b ▁In ▁the ▁ 1 9 5 0 s ▁and ▁ 1 9 6 0 s , ▁there ▁were ▁occas ional ▁newspaper ▁reports ▁of ▁clim bers ▁who ▁had ▁made ▁illegal ▁arch ▁travers als ▁of ▁the ▁bridge ▁by ▁night . ▁In ▁ 1 9 7 3 ▁Philippe ▁Pet it ▁walked ▁across ▁a ▁wire ▁between ▁the ▁two ▁p yl ons ▁at ▁the ▁southern ▁end ▁of ▁the ▁Sydney ▁Har bour ▁Bridge . ▁Since ▁ 1 9 9 8 , ▁Bridge C lim b ▁has ▁made ▁it ▁possible ▁for ▁tour ists ▁to ▁leg ally ▁clim b ▁the ▁southern ▁half ▁of ▁the ▁bridge . ▁T ours ▁run ▁throughout ▁the ▁day , ▁from ▁dawn ▁to ▁night , ▁and ▁are ▁only ▁cancel led ▁for ▁elect rical ▁storm s ▁or ▁high ▁wind . ▁ ▁Gr oups ▁of ▁clim bers ▁are ▁provided ▁with ▁protect ive ▁cl othing ▁appropriate ▁to ▁the ▁prev ail ing ▁weather ▁conditions , ▁and ▁are ▁given ▁an ▁orientation ▁brief ing ▁before ▁clim bing . ▁During ▁the ▁clim b , ▁at ten de es ▁are ▁secured ▁to ▁the ▁bridge ▁by ▁a ▁wire ▁lif eline . ▁Each ▁clim b ▁begins ▁on ▁the ▁eastern ▁side ▁of ▁the ▁bridge ▁and ▁asc ends ▁to ▁the ▁top . ▁At ▁the ▁sum mit , ▁the ▁group ▁cross es ▁to ▁the ▁western ▁side ▁of ▁the ▁arch ▁for ▁the ▁descent . ▁Each ▁clim b ▁takes ▁three - and - a - half - h ours , ▁including ▁the ▁prepar ations . ▁ ▁In ▁December ▁ 2 0 0 6 , ▁Bridge C lim b ▁launched ▁an ▁alternative ▁to