Context: European colonialism in the Sahara began in the 19th century. France conquered the regency of Algiers from the Ottomans in 1830, and French rule spread south from Algeria and eastwards from Senegal into the upper Niger to include present-day Algeria, Chad, Mali then French Sudan including Timbuktu, Mauritania, Morocco (1912), Niger, and Tunisia (1881). By the beginning of the 20th century, the trans-Saharan trade had clearly declined because goods were moved through more modern and efficient means, such as airplanes, rather than across the desert.

Question: What time period did the colonialism of the Sahara begin?
Answer: 19th century

Question: What country conquered the Algiers from the Ottomans in   1830?
Answer: France

Question: During what time were good moved through more modern   means?
Answer: 20th century

Question: When did the Ottomans conquer France?
Answer: Unanswerable

Question: What caused trans-Saharan trade to take off in the 20th century?
Answer: Unanswerable

Question: What area of the regency of Algiers was not under French control?
Answer: Unanswerable

Question: When did France relinquish control of Morocco?
Answer: Unanswerable

Question: What year did France conquer Niger?
Answer: Unanswerable