What is the difference between Silicon Valley and the San Francisco Bay Area? Is San Francisco a city or a county? Where in the Bay Area are the headquarters of the largest tech companies in the world? 
 
This video explains the difference between San Francisco, Silicon Valley, and the Bay Area, gives brief overview of the history of Silicon Valley and how it came to dominate the tech industry, and gives you a tour of the Bay Area along with the companies headquartered there.  
 
Image Credits: 
 
Golden Gate Bridge: Rich Niewiroski Jr. - http://www.projectrich.com/gallery 
Bay Bridge: Leonard G 
San Francisco Skyline along Market Street from Twin Peaks: Vincent Bloch 
San Francisco Street Map: Peter Fitzgerald, OpenStreetMap 
Government Levels Responsibilities Sprites: Freeciv 
Golden Gate Bridge driving away from SF: Weegee010 
California Central Valley: LTSLTS 
SV Family Tree/ Fairchildren graphic: IEEE Spectrum Magazine, October 2007 
San Francisco Bay Area County Maps: Wikipedia Community 
California Counties Map: Wikipedia Community 
Map of North America: NuclearVacuum 
 
 
Links for mobile users: 
 
CGP Grey video which talks about Cities, Counties, and Incorporated vs Unincorporated places: https://www.youtube.com/watch?v=naDCCW5TSpU 
 
Crash Course Government video on the separation of powers: https://www.youtube.com/watch?v=J0gosGXSgsI 
 
Moore's Law: https://www.youtube.com/watch?v=rtI5wRyHpTg 
 
Numberphile: https://www.youtube.com/user/numberphile 
 
The difference between UK, GB, and England Explained: https://www.youtube.com/watch?v=rNu8XDBSn10 
 
10 Funny Trolley Problems (On my other channel): https://www.youtube.com/watch?v=yywd3bXfYAg 
 
Why is San Francisco so expensive?: https://www.youtube.com/watch?v=AAlA4hZ94OI 
 
Mistakes:  
 
Moore's first name is Gordon, not George 
Lucasfilms moved to San Francisco in 2005, but much of the operation remains in Marin 
Pronounciation