In Raiders of the Lost Ark, the opening jungle adventure is set in 1936.
The film begins with Indiana Jones entering a Peruvian temple to retrieve a golden idol. Its opening title card identifies the year as 1936, establishing the story’s pulp-adventure setting shortly before World War II.
This date is sometimes confused with 1935, the year used for the main story of Indiana Jones and the Temple of Doom. Temple of Doom is a prequel in the fictional chronology, even though it was released after Raiders of the Lost Ark.
The 1936 setting also helps explain why the film’s later search for the Ark of the Covenant involves Nazi agents. The archaeological race takes place before the United States enters the war, while Nazi Germany is already pursuing powerful cultural and religious artifacts.