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Fans gathered en masse around the 18th green during second-round action on Friday.

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Defending champion Rory McIlroy blasted out of a bunker on the 10th hole during the second round.

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Charlie Wi launched his tee shot on the 11th hole on Friday.

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World No. 1 player Luke Donald had to hit his third shot on the 11th hole Friday from the bunker.

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Matt Kuchar closely followed the track of his putt on the seventh hole on Friday.

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Fans on the 18th hole watched from the grandstands as Rory McIlroy played his shot on Friday.

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Ian Poulter sprayed some sand as he played a bunker shot on Friday.

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Graeme McDowell, US Open champion in 2010, tried to land his shot on the ninth hole inside the myriad bunkers around the green on Friday.

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Michael Thompson was the surprise leader after round one. His score of 4-under par bested the field by three shots and he was one of four players under par.

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The first day of the US Open opened with the power pairing of Tiger Woods, left, and Phil Mickelson, two of the first players to tee off.

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Hundreds of people crowded around the tee boxes to watch Woods, in pursuit of his major since 2008.

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This year's US Open is being held the Olympic Club in San Francisco. The course has no water, but treacherous bunkers.

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Scenic views of San Francisco can be scene from the course, which is hosting its fifth US Open.

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Fans packed the course for the opening round, some with interesting devices to get them different views of the action.

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As if the Tiger Woods-Phil Mickelson pairing weren't enough, the duo was playing with Masters champion Bubba Watson.

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Amateur Andy Zhang, shown teeing off on the fourth hole, was the youngest player in the field at 14.