Media playback is unsupported on your device

San Francisco's tech boom 'changing the soul of the city'

31 January 2014 Last updated at 11:12 GMT

The centre of the technology world has traditionally been Silicon Valley in California.

But 30 miles north, San Francisco is now home to a staggering 2,000 tech companies, including the likes of Twitter and Instagram.

Some say it is "changing the soul of the city".

Richard Taylor reports.

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.