what was the biggest threat to Tenochitlan.To solve this problem were built to protect the city.

Chronological order events of the Russian Revolution:Czar Nicholas II ascends the throne - In November 1894 after the death of his father Alexander III World War I begins - In 1914 after the Austrian Archduke is killed. Food and Fuel shortages lead to widespread revolts - In 1917 after Czar Nicholas and his machinery fails to fetch supplies of food from Siberia and from the rest of the world. Czar Nicholas's family is murdered by the Red Army - In July of 1918 in the town of Ekaterinburg. The Union of Soviet Socialist Republic is established​ - 30th December 1922.