Complex sentence: On September 6,1978, Jim Wickwire and Louis Reichardt reached the summit of K2 via the Abruzzi Spur; the following day, Rick Ridgeway and John Roskelley made the summit via the NE Ridge, a route that has never been repeated.
Split into simpler sentences: On September 6,1978, Jim Wickwire and Louis Reichardt reached the summit of K2 via the Abruzzi Spur. The following day, Rick Ridgeway and John Roskelley made the summit via the NE Ridge, a route that has never been repeated.