Coit Tower sits atop Telegraph Hill in Pioneer Park and offers a spectacular 360-degree view of the bay, bridges, and surrounding neighborhoods. It can be reached via footpaths on the east side of Telegraph Hill, or via Telegraph Hill Boulevard. It is a popular tourist destination.
There are also some pretty cool 1930s-era murals inside the base of the tower. There's quite a bit of history about the murals which originally included one by Diego Rivera Along with the Golden Gate Bridge, this structure is probably one of the best examples of art deco architecture in San Francisco.
Sadly, it costs money to ride the elevator up to the top of the tower, and there's usually quite a wait. The cost is $4.50 and the wait can be up to 40 minutes. The elevator operator will give a mini-history of the tower and when you get to the top you get to view a 360-degree panorama of the city through Plexiglas windows.
If you decide to walk to Coit Tower, you'll encounter one of the city's many outdoor concrete staircases. Go around another way and you'll see wooden staircases in a beautiful hidden garden.