As you stand below in the valley, and cattails are carpeting the floor, you see as a backdrop the huge Sentinel Rock, standing guard straight and tall. This huge spire is opposite Yosemite Falls in Yosemite National Park and is a favorite for photographers.
One of the best views you can get is when you stop at the turnout at Tunnel View. This is reached by entering the park on Highway 41 and is one of the most popular for getting great photos of Sentinel Rock and Half Dome along with Cloud's Rest in the distance.
This petrified tower stands 3,073 feet over the south side of the valley. If you are on Four-Mile Trail you can see how the sun catches it beautifully. This trail climbs the valley wall to the left. Sentinel Dome at 8,122 feet looms above this whole scene. In the spring, Sentinel Falls cascades down beside this monolith.
Climbing is popular at either Sentinel Rock or Sentinel Dome. Sentinel Rock can be ascended by using a steep gully on its east side. If you prefer to tackle the dome, from Glacier Point you can take a ranger-narrated walk for a 180-degree view from the top.