Inside Facebook’s Silicon Valley headquarters

Facebook CEO and cofounder Mark Zuckerberg at their 12th anniversary event at their headquarters in Menlo Park, CA.

Inside building 20.

The Instagram offices on the Facebook campus.

Facebook COO Sheryl Sandberg holds three-month-old Sohana Gulati during their 12th anniversary event.

Using a bicycle to pull bikes on the Facebook campus.

Laneyse Hooks hugs a another participant at an event at Facebook to celebrate Facebook Friends day, the company's 12th anniversary.

A bike repair shop for employees at the Facebook campus.

The Facebook campus.

Facebook employees board buses on the Facebook campus in Menlo Park, CA.

Exterior of Building 20 on the Facebook campus.

Exterior of Building 20 on the Facebook campus.

On the Facebook campus in building 20.

A costumed reveler walks the halls of Building 20.

Laundry service for employees inside Building 20.

On the Facebook campus in building 20.

On the Facebook campus.

On the Facebook campus.

Inside building 20.

On the Facebook campus.

Inside building 20.

An interview room inside building 20.

Working inside building 20.

The Facebook campus is located at 1 Hacker Way in Menlo Park, CA.

Inside building 20.

Inside building 20.

Facebook COO Sheryl Sandberg at their 12th anniversary event.

Inside building 20.

Inside building 20.

Facebook CEO and cofounder Mark Zuckerberg.

An old American Motors Pacer on display.

By 2030, Facebook aims to have 5 billion of the world’s 7 billion humans connected to its social network.

The corner of Hacker Way and Willow Road on the Facebook campus.

Visitors pose for photos on the Facebook campus.

This is the inside of building 20 on the Facebook campus.

This is the inside of Building 20 on the Facebook campus located at 1 Facebook Drive in Menlo Park, CA.

Facebook CEO and cofounder Mark Zuckerberg take a a selfie at their 12th anniversary event at their headquarters in Menlo Park, CA.