As we are limited in space, below are a few ideas about the Aztecs and The Crusades to help get you started.
The Aztecs were a group of people who existed in what is now Mexico starting in the 14th century, prior to Christopher Columbus sailing to America, and lasting until the 16th century. The Aztecs built a very strong empire composed of an alliance of three city states: Tenochtitlan, Texcoco, and Tlacopan. The empire became a dominant power through military invasion and trade. The Aztecs were important, even to modern day Mexico, because they were a particularly innovative group of people. They made great advancements in astronomy and botany. Plus, they were an agrarian culture that developed terrace agriculture to farm Mexico's hilly regions; they also used irrigation farming, building dams to distribute the natural spring water to the fields and canals to distribute the Cuauhtitlan River to the fields.
The Crusades started centuries before the development of the Aztec empire but lasted until the 15th century, one century before the fall of the Aztecs. The Crusades were a series of wars the Roman Catholic Church launched against Islam because both Islam and the Church battled for dominance over the Holy Land, meaning Jerusalem. Though there were other crusades beginning in 718 a.d., there was also a series of nine different crusades that began in 1095, as well as the Aragonese Crusade, a crusade against the King of Aragon, and the final crusades in the 15th century that leading to the fall of Constantinople. The Crusades had many significant impacts. One impact was increasing trade along the Mediterranean, especially increasing trade in Genoa and Venice, turning these cities into the thriving wonders we know today. What's more, during the Crusade movement, the power of the Church became centralized under the leadership of the pope. finally, the Crusades led to the ransacking and capture of Constantinople, leading to the fall of the Byzantine Empire, the Greek-speaking portion of the Roman Empire, to the Ottomans, or the Turks.