Complex sentence: A gas explosion takes place at Gresford Colliery in Wrexham, north-east Wales which leads to the death of 266 miners and rescuers, one of the worst tragedies in Welsh mining history.
Split into simpler sentences: A gas explosion takes place at Gresford Colliery in Wrexham, north-east Wales which leads to the death of 266 miners and rescuers. This is one of the worst tragedies in Welsh mining history.