The processes of genetic mutation and recombination are fundamental drivers of viral evolution. Mutations introduce small changes within the genome, which are often visible in sequencing data. Recombination occurs when the same cell is co-infected by two different strains, whose genetic material is mixed together during replication - creating hybrids that potentially possess very different pathogenic properties. The detection of recombination events from a sample of genetic data is a very challenging problem. I will show how possible genealogical histories can be reconstructed from sequencing data, and explain how this can be used to detect ongoing recombination.