A Delta Quadrant people whose colonists on Tarakis were slaughtered during a forced evacuation, an atrocity recorded by a memorial that transmits the memory to passers-by.
The Nakan are remembered in the Voyager episode Memorial. Roughly three centuries before Voyager's arrival, a military unit under a commander named Saavdra was ordered to move a colony of eighty-two Nakan off the planet Tarakis. The colonists resisted, shooting broke out, and the soldiers killed them all and then destroyed the evidence.
Someone later built an obelisk on the planet which implants the event directly into the minds of anyone who comes near, so that it will never be forgotten.
In 2376 Chakotay, Paris, Kim and Neelix return from a two-week away mission haunted by memories of taking part in the killings, and the rest of the crew are soon affected. Finding the failing memorial, Janeway decides against shutting it down. She has it repaired and leaves a warning buoy for other ships.