Complex sentence: On the Easter weekend of 1964 rival youth gangs of Mods and Rockers descended upon Clacton-on-Sea and wrecked the place starting fights with each other and vandalising streets and shops.
Split into simpler sentences: On the Easter weekend of 1964 rival youth gangs of Mods and Rockers descended upon Clacton-on-Sea. They created havoc by starting gang fights with each other and vandalising streets and shops.