While the head of China isn't an emperor, but a president (H.E. Hu Jintao), several royal lines, namely the descendants of the Han, Tang, Song, Ming Emperors are likely still alive and well. If migration, bloodline, and ancestry are traced, one will find what could be the equivalent of heads of Royal Families still holding given clan names. Zhu Rongji is one such candidate.
Under Frankish law, a kingdom did not pass to a single heir, but was distributed among the heirs. Under the Carolingian Empire, this was modified only to the point of having the empire go to a single heir, but there were numerous kingdoms controlled by different kings. The various kings quarrelled, and the overall emperor was only able to get support from his own kingdom, not from the empire as a whole, so the empire passed to a powerless state. Later, it was revived, but France remained separate from it; in this revived form, it was called the Holy Roman Empire.
Nobody. Certainly no single power. Western Europe collectively came closest in geographical reach, yet large areas of the globe were beyond its control: the emperor of a third of the world's population had just told a British emissary to China that he wasn't interested. Assertions of hegemony are usually gross exaggerations and oversimplifications: the world doesn't work like that.
The Euro was created in 1957. It was created to make a single currency throughout Europe. Single currency has many advantages.
Engand & France were becoming nations unified under a single ruler.
Charlemagne
No, Charles Darwin is not single.
No, Charles Dickens is not single.
No, Charles Bukowski is not single.
No, Charles Lindbergh is not single.
No, Charles bronson is not single.
No, Charles Evers is not single.
No, Charles Stanley is not single.
No, Charles de Gaulle is not single.
There never was a single Emperor of Africa.
Binary fission is best applied to describe the asexual reproduction process in which a single parent cell divides into two identical daughter cells. This term is commonly used in reference to prokaryotic organisms such as bacteria, which reproduce by binary fission.
Hillary is single. Charles is married.