Complex sentence: The Challenge Stakes is a Group 2 flat horse race in the United Kingdom for three-year-old and above thoroughbreds run over a distance of 7 furlongs (1,408 metres) at Newmarket's Rowley Mile course in October.
Split into simpler sentences: The Challenge Stakes is a Group 2 flat horse race in the United Kingdom for three-year-old and above thoroughbreds. It is run over a distance of 7 furlongs (1,408 metres) at Newmarket's Rowley Mile course in October.