After the Seljuk Turks emerged as a major factor in eastern Islam, they conquered two regions that were not previously part of Dar al-Islam: Asia Minor and northern India near Delhi. Here, take a comparative look at these conquests, including the Turks' seesaw struggle with the crusaders.

Observe how the measurement of factors such as electromagnetic radiation, hydration, and carbon content can reveal the age of excavated objects. Examine how particular environmental conditions can preserve organic material over centuries or millennia. Finally, take account of the looting of antiquities and its impact on the world’s archaeological heritage.

At its height around 400 AD, Teotihuacan was the most populous city in the western hemisphere. Explore this vibrant metropolis, focusing on its still-extant pyramids of the Sun and Moon and the role they played in the violent ritual life of the Classic Maya period.

After the Battle of Talas, Islamic expansion halted for 300 years. Explore Baghdad's emergence as an intellectual and economic center of the Islamic world as well as the religion's cultural achievements during this period, particularly in architecture. Then, learn why Turkish merchants converted to Sunni Islam - or their version of it - starting in the 8th century.

Born a slave, he was exiled from Rome for speaking too freely to the emperor. Despite offers to return, he lived on in a backwater, becoming one of the greatest exponents of that vastly influential approach to life known as Stoicism.

Genghis Khan's rivals saw him as the embodiment of the steppe barbarian. But who was this man who united the Mongol tribes and set his sights on world conquest? Discover Temujin - as Genghis Khan was originally known - and who the Mongols were at the time of his birth.

Despite centuries of assimilation and persecution, Maya culture still thrives. Investigate its survival in Guatemala, where 80 percent of the population is Maya, living largely in traditional ways. Dr. Barnhart describes his own observations from extensive visits to the country.

To the senator and historian Tacitus, Nero illustrated the grim reality of the principate and the fate of the Roman people, who had surrendered liberty for security only to find their fate in the hands of a mad tyrant.

Begin the series on the outskirts of Rome, taking the Via Appia into the city. View the impressive tombs and aqueducts that line the road, testifying to the importance of the ancient capital. Within, visit major sites that include the extensive ruins of different forum spaces and temples. Also, explore subterranean Rome, and sample the market and café scene, as lively today as two millennia ago.

The Aztecs claimed that their civilization descended from the mighty Toltecs. But were the Toltecs as magnificent as the Aztecs believed? Join the hunt for this elusive empire, which was headquartered at the modest town of Tula and spread influential ideas such as the legend of Quetzalcoatl.