Answer
Zecharia Sitchin's major contributions to pseudoscience are his theories about ancient astronauts. Sitchin argued that the ancient Sumerians were visited by an extraterrestrial race known as the Anunnaki, who taught the Sumerians how to build civilizations and also created humans as a slave race to mine gold for them. Sitchin's theories have been widely criticized by scientists, who point out that there is no evidence to support them.