What is it about the lure of the danger? Take a walk on the wild side at Sibley Volcanic Regional Preserve [6800 Skyline Blvd Oakland, CA 94611]. The drive there is something special to begin with if you take Grizzly Peak Blvd, on one side you have some epic mansions and the other you have this dazzling view.
When you get to the park you’ll walk upon a 10 million years old volcano, today Round Top is one of the tallest peaks in the area made up of lava.
Take a self guided geology tour and a hike. I was on a mission for something a bit mysterious, a volcanic labyrinth.
Hike to Quarry Pit 2 and look down, you’ll find your way. 
The soft velvety hills are mellowing, the views in the park are stunning,
and you’ll find plenty of interesting flora and fauna.
There are numerous trails to take including a section of the 31-mile East Bay Skyline National Recreation Trail, Bay Area Ridge Trail, and of course to the summit of Round Top.