The East Bay Regional Park District has many stunning hikes. I suspect a Bay Area native can spend many weeks a year just exploring the trails in the East Bay. One of the really pretty areas to hike has to be Briones Regional Park. There are many trails in the area, but Raja found this gorgeous section to hike.
This hike took us along the Old Briones Road to the summit to see sweeping views of Martinez peninsula and waterways.
https://www.strava.com/activities/4981721710
Stunning views from the summit.
From the summit, you get to see Carquinez Bridge and the Delta.
Briones Regional Park offers a lot of hikes with sweeping views of Martinez area, must visit during Spring.