Facebook today published an explanatory post from engineers who worked on the popular “Look Back” feature the company launched as part of its 10th anniversary. The company revealed the project went from an imagined concept to a completed product in under a month.

Here are a few interesting data points the company underlined:

  • Over 720 million Look BAck videos were rendered, with an average of 9 million videos rendered per hour.
  • More than 11 petabytes of storage was used.
  • More than 450 Gbps outgoing bandwidth at peak and 4PB egress within days.
  • Over 200 million people watched their Look Back video in the first two days, and more than 50 percent who saw it shared it.

Facebook says it anticipated only 10 percent of people who saw their video would share it, but that number quickly started at over 40 percent and ended up even higher by the end of the project. Since it came out of nowhere, no official team owned the Look Back feature; 30 teams at the company worked together to finish it in time.

Looking back on “Look Back” videos

Image Credit: Karen Bleier/AFP/Getty Images