The death of James T. Kirk on Veridian III in 2371, after he left the Nexus to help Jean-Luc Picard stop Soran's launcher.
Kirk dies at the end of Star Trek Generations. In 2293 he was thought killed when the Nexus ribbon tore open the hull of the Enterprise-B. He had instead been drawn into the Nexus, where time has no meaning. Picard finds him there, chopping wood at a mountain cabin, and persuades him to return and make a difference once more.
The two arrive on Veridian III minutes before Soran fires his probe. They fight him on the scaffolding, and Kirk leaps across a broken bridge to reach the control pad, allowing Picard to lock the launcher in place. The probe explodes on the pad and kills Soran.
The bridge collapses with Kirk on it. Picard reaches him as he dies and buries him under a cairn of stones on the mountain top.