Once at the top, there is a small visitor center. It used to be a radar site to detect invasions, and was eventually shut down and left to rot. Eventually it was re-habilitated close to its original aspect and turned into a small park with nice views.

The 4 peaks of the bay area, Mt Umunhum, Mt Hamilton, Mt Diablo, and Mt Tamalpais.

The park is actually a very short walk, but the viewpoint is good on a clear day. There are a few signs you can read and an audioguide you can get on android:

Mt Hamilton across the bay

Old radar building that was used to detect potential enemy planes coming from the pacific

Respect to the native americans who used to live here