YOSEMITE NATIONAL PARK, Calif. — President Obama and the first family arrived here late Friday for a weekend tour of one of the nation's most breathtaking national parks, and they got a rare view of the place.

Marine One and several support helicopters, including a Chinook carrying the traveling media pool, soared above the valley, weaving through tree-covered peaks and past steep waterfalls. The setting sun illuminated Half Dome, the shimmering granite rock face in the park's eastern end, and a nearly full moon was rising as the helicopters made their approach to a grassy field.

A crowd had gathered just beyond the field behind a rope barrier set up by the Secret Service, but the field itself was mostly empty as the first family prepared to exit the helicopters.

The president's trip, timed to the 100th anniversary of the creation of the national park system, is aimed in part at highlighting his administration's efforts to preserve federal lands and the environment. The use of the presidential helicopters came in for some criticism on social media for the noise and disruption to the environment in Yosemite. Obama is expected speak about the importance of the parks on Saturday.

After exiting the helicopters and walking about 30 yards through the grass, the Obamas stopped to speak with park rangers and staff, then greeted the crowd briefly before entering the presidential motorcade for a short drive to their lodge for the night.