Zinj is the name of a city that features in the novel Congo and its movie adaptation.
The city of Zinj was constructed at an unspecified moment in the past and was located in the Virunga region of the Congo in Africa. Its position was also a rich site that contained diamonds in the region which was discovered by King Solomon who established a mine in the region to gather the precious gem. During this time, a settlement was established and heavily guarded by the inhabitants in order to secure the safety of King Solomon's mines. A number of hieroglyphs were engraved in stones throughout the city and surrounding area that translated to "We are watching you" in order to deter any trespassers. Another act conducted by the inhabitants of Zinj was the breeding of a guardian animal which involved the native gorillas that populated the region. Taking these animals, the people of Zinj managed to create a hybrid animal that was not strictly a true gorilla but rather one that contained characteristics of either a human or a chimpanzee. Their mass and height were ntoable for being closer to that of a human with a malformed skull along with a skin pigmentation that bordered on albinism with light gray fur as well as yellow eyes. This new species completely different behavior as they were much more aggressive, ruthless and demonstrated nocturnal qualities by attacking at night in large groups. These creatures were deemed the perfect guard animals for the city as they were reasonably intelligent and violently defended their home territory.
At some point, the city was abandoned by all the human inhabitants and its position became something of a legend with it being known as the Lost City of Zinj. The only inhabitants of the region were the animal ape guardians who remained devoted protectors of the abandoned city along with its precious diamonds. An African ghost tribe were the closest village to the lost city and kept the area a wide berth due to the warnings that informed trespassers to stay away from that region. Over the centuries, many safari expeditions were conducted in Africa in order to find the City of Zinj though none were deemed successful. However, a detailed drawing of the City of Zinj was once made in a book that later found itself in Soviet Georgia and also claimed that King Solomon had kept a diamond mine in the abandoned settlement. A young Herkermer Homolka learnt of the existence of Zinj from this book and became determined to uncover its existence in the future. By the 20th century, a gorilla known as Amy was known to had visited the city before returning to the wilds of Africa. She was later taken in by a scientific group that were studying primates which consisted of a primatologist known as Peter Elliott who had devised a means to communicate with gorillas using sign language as well as a electronic translation unit. During her time with Elliott, Amy constantly draws the City of Zinj that she had once visited though none of her keepers were aware of what she was drawing at the time.
By the late 20th century, a corporation known as TraviCom (in the novel its called Earth Resource Technology Services Inc) uncovered the diamonds which they intended to make use of them for optical communication (though the novel states its due to their semiconductor properties). Sending an expedition into the mines to harvest them of their diamonds, the members of the group became viciously attacked by the hybrid gorillas who killed most of the intruders. This forced Dr Karen Ross to take another expedition to uncover what happened to their predecessors as well as gather more of the diamonds before other groups decide to claim the region. Knowing of the gorilla attack, she recruits the aid of primatologist Peter Elliott and the expedition was funded by the efforts of an older Herkermer Homolka. Travelling to Congo, they mange to uncover the Lost City of Zinj with the aid of Amy and learn of its aggressive defenders which Peter Elliott intended to call Gorilla elliotensis after himself. Over the course of events, Ross made use of explosives as part of her geological survey which had the unintended side effect of triggering an eruption from the nearby volcano. This act not only destroys the city but seemingly wipes out its new species of gorilla guardians as well as left its treasures of diamonds trapped beneath the lava thus bringing about the end of the Lost City of Zinj.