Complex sentence: In 1948, the Hells Angels formed in Fontana, California as a motorcycle club looking for excitement in the dull times after the end of the war and became notorious as time passed.
Split into simpler sentences: In 1948, the Hells Angels formed in Fontana, California. The Hells Angels began as a motorcycle club looking for excitement in the dull times after the end of the war and became notorious as time passed.