BacMap is a freely available web-accessible database containing fully annotated, fully zoomable and fully searchable chromosome maps from more than 2500 prokaryotic (archaebacterial and eubacterial) species. BacMap was originally developed in 2005 to address the challenges of viewing and navigating through the growing numbers of bacterial genomes that were being generated through large-scale sequencing efforts. Since it was first introduced, the number of bacterial genomes in BacMap has grown by more than 15X. Essentially BacMap functions as an on-line visual atlas of microbial genomes. All of the genome annotations in BacMap were generated through the BASys genome annotation system. BASys is a widely used microbial annotation infrastructure that performs comprehensive bionformatic analyse