Almost all of the major early civilizations of South America emerged in the Andean foothills. These civilizations include the Moche, the Nazca, the Chavin, and the Inca.

The Celts are an ancient ethnic group who emerged in modern-day France and migrated around Western Europe, settling in places like Spain, Germany, and (most impactfully) the British Isles.

The Nazca people emerged in modern-day Peru, on the Pacific coast, around 100 CE.

The Anasazi culture emerged in the southwest of the modern-day United States. The Anasazi lived in this part of North America from about 300 - 1300 CE.

During the High Middle Ages up until the 1340s, the relatively large European population continued to slowly increase over the course of a few centuries.  The Black Death of the 1340s and early 1350s resulted in a massive demographic collapse, followed by slow but steady growth amongst a much smaller population during the 1400s.

The Toltec civilization existed in modern-day Mexico between approximately 900-1100 C.E. Much of what we know comes from recent architectural digs, but also from the Aztecs who saw the Toltecs as their cultural predecessors. They are famous for the construction of pyramids, much like those used by the Mayans and Aztecs.

The Vikings were seafaring warriors, traders, and settlers who were widely influential from the eighth to the thirteenth centuries. The longship was developed by the Vikings in the ninth century and was instrumental in allowing the Vikings to traverse long distances at icy northern latitudes. It allowed the Vikings to cross the Atlantic and establish colonies in Greenland and North America in the tenth and eleventh centuries.

The Moors were North African Muslims who had conquered the Iberian Peninsula in the 800s. Religious conflict with the Christian powers of Europe led to frequent conflicts, with their loss of regional power in 1492 with the fall of Grenada, and the full elimination of Muslims from Spain in 1609.

Although some historians theorize that Zheng He might have eventually made a voyage across the vast Pacific Ocean, to the New World, this is merely conjecture. The voyages of Zheng He, and his fleet, were primarily conducted in the South China Sea and the Indian Ocean. He did reach such distant places as the Swahili city-states of East Africa and Red Sea.

Al-Andalus is the name given to Islamic Spain. After the initial expansion of Islam, under the Umayyad and Abbasid caliphates in the seventh and eighth centuries, much of the Iberian peninsula (modern-day Spain and Portugal) was under the control of Islam. This region was called Al-Andalus and was under almost complete control of the Umayyad dynasty until the tenth century. Islamic control over parts of Spain would persist until the fifteenth century.