A genomic inversion is when a region of a genome or chromosome gets flipped in place. These usually happen at genomic regions with nearly identical sequence, implying a mechanism similar to non-homologous recombination.
Bacteria
In bacterial genomes, inversion often occur at transposon or ribosomal gene sequences, and happen symmetrically around the origin of replication. The latter causes a characteristic pattern in syntenic dotplots called an x alignment.