SELECT COMMISSIONS >: National Geographic: Silicon Valley: SiliconValley_0001

A commuter riding a Onewheel electronic skateboard passes by the building that houses the headquarters of Twitter, located in the Mid-Market neighborhood, in San Francisco, Calif., on September 21, 2018. In 2011 San Francisco passed the controversial Central Market Tax Exclusion to encourage companies to move into the Mid-Market and Tenderloin neighborhoods. Tech giants such as Twitter, Dolby and Uber are now located in the area.

A commuter riding a Onewheel electronic skateboard passes by the building that houses the headquarters of Twitter, located in the Mid-Market neighborhood, in San Francisco, Calif., on September 21, 2018. In 2011 San Francisco passed the controversial Central Market Tax Exclusion to encourage companies to move into the Mid-Market and Tenderloin neighborhoods. Tech giants such as Twitter, Dolby and Uber are now located in the area.