The first place most people go when they reach Yosemite National Park [1] is the floor of Yosemite Valley (Hwy. 140, Arch Rock Entrance). From the Valley floor, you can check out the visitors center [2], theater, galleries, museum, hotels, and outdoor historic exhibits.
Numerous pullouts from the main road invite photographers to capture the beauty of the Valley and its many easily visible natural wonders. It’s the most visited place in Yosemite, and many hikes begin in the Valley [3], ranging from easy to difficult.
Links:
[1] http://www.moon.com/destinations/california/yosemite-and-the-eastern-sierra/yosemite-national-park
[2] http://www.moon.com/destinations/california/yosemite-and-the-eastern-sierra/yosemite-national-park/sights/yosemite-valley/visitors-center
[3] http://www.moon.com/destinations/california/yosemite-and-the-eastern-sierra/yosemite-national-park/hiking/yosemite-valley