We are excited to announce that Social Science One and Facebook have completed, and are now making available to academic researchers, one of the largest social science datasets ever constructed. We processed approximately an exabyte (a quintillion bytes, or a billion gigabytes) of raw data from the platform. The dataset itself contains a total of more than 10 trillion numbers that summarize information about 38 million URLs shared more than 100 times publicly on Facebook (between 1/1/2017 and 7/31/2019). It also includes characteristics of the URLs (such as whether they were fact-checked or flagged by users as hate speech) and the aggregated data concerning the types of people who viewed, shared, liked, reacted to, shared without viewing, and otherwise interacted with these links. This dataset enables social scientists to study some of the most important questions of our time about the effects of social media on democracy and elections with information to which they have never before had access. The full codebook for the dataset is here.