Silicon Valley is in the south bay, and is surrounded by many hills. For those who enjoy hiking, Almaden Quicksilver County Park (http://www.geocities.com/...) provides many hiking trails. From the San Jose Airport, head south in Highway 87 until Almaden Expressway. Drive south on Almaden until Camden Avenue and take a right. On Camden, drive until McAbee Road, and take a left. Drive to the end. There are various other entrances as well, but this is known as the main entrance.
