LOS ANGELES (AP) -- There was no stopping "Limitless" at the box office.
The sci-fi thriller opened at No. 1 this weekend with $19 million, according to studio estimates Sunday.
The film from Relativity Media stars Bradley Cooper as a struggling writer who takes a magical pill that allows him to tap into his maximum brain potential. Suddenly he's cleaned up, making millions and wowing everyone he meets.
Robert De Niro co-stars as a financial guru who's fascinated by him, with Abbie Cornish as Cooper's skeptical girlfriend.
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