A Sound of Thunder
(2005)

During one of the Time Safari trips into the past, one of their clients accidentally steps off "the path" and kills a butterfly. This small incident sets off an immediate chain reaction in the future with dramatic climatic changes and the growth of deadly plant and animal life.
 
Travis Ryer (Ed Burns) and the inventor of the time travel device Sonia Rand (Catherine McCormack) manage to send him back to the original trip that caused the damage. Ryer manages to warn a member of his team of the dangers of their trips to the past and stop Charles Hatton's (Ben Kingsley) greedy exploitation of the time technology. The last scene is Travis visiting Sonia and giving her proof that Hatton will destroy Earth as they know it if he isn't stopped.

Thanks Kay W!

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