cross-wire to mark the center

Now, a ceremony has been held to mark the 100th anniversary of its opening.
さて、その開通１００周年を記念する式典が開かれました。

to mark the 40th anniversary of the war's end
終戦40周年で

to mark the 60th year of the Emperor's reign
天皇御在位60周年を記念して

ceremony to mark the start of enforcement of the Kyoto Protocol
京都議定書の発効記念式

cross-wire to mark the center
中心を示すための十字線