FamilySearch, a nonprofit genealogical society affiliated with the Church of Jesus Christ of Latter-day Saints, uses Apache Cassandra™ to help users learn more about their families' histories. The organization has three main use cases for Cassandra: enabling users to access information about their families and collaborate with other family tree researchers; facilitating a hinting app that guides people to additional research resources; and helping researchers track down records related to their ancestors based on specific qualifiers. FamilySearch processes millions of reads/second and writes/second, making it an excellent example of how Cassandra can be used at scale for large-scale family history research.