Researchers discovered that as many as 600 million birds die in the US every year after flying into skyscrapers.
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German mathematician Carl Friedrich Gauss became the first person to prove quadratic reciprocity law.
Democratic Senator Bernie Sanders dropped out of the race for US president.
Racer Bob Burman died after crashing his race car in Corona, California.
NASA's Discovery space shuttle launched on mission STS-56.
Clint Eastwood was elected as Mayor of Carmel, California.
