Skin Cells

 Does thinking about this make your skin crawl? Ours, too. The epidermis (upper layer of skin) is consistently replacing itself. Skin cells usually last around 2-3 weeks. While that sounds extreme, the epidermis is not the only one renewing itself — the cells in your colon die off even faster, with four day life spans. On the other hand, not all cells replace themselves. Brain cells typically last an entire lifetime… which is good news, because most of us aren't in the market to be losing brain cells!

Hundred Years' War

 The Hundred Years' War was a series of armed conflicts that pitted the kingdoms of France and England against each other during the Late Middle Ages. Despite its name, the war actually lasted for 116 years, between 1337 and 1453. It originated from disputed claims to the French throne between the English royal House of Plantagenet and the French royal House of Valois. During the war, five generations of kings from two rival dynasties fought for the throne of the largest kingdom in Western Europe. The war was eventually won by the French at the Battle of Castillon.

Roman Numeral "C"

 

The number 100 is represented by the letter "C" in Roman numerals.

Roman numerals are a numbering system that originated in ancient Rome and was widely used across Europe until the late Middle Ages. Combinations of letters from the Latin alphabet are used to represent numbers in this system.

Long after the Roman Empire fell apart, Roman numerals were still used. Roman numerals started to be phased out in favor of Arabic numbers in the 14th century; however, this transition was slow, and Roman numerals are still used in certain applications today. Clock faces are one of the most common places where they may be found.

Instead of using place value notation, Roman numerals utilize a set of symbols with defined values, including "built in" powers of ten. Tally-like combinations of these fixed symbols correspond to Arabic numerals' digits. This structure allows for a lot of variation in notation, and there are a lot of them.

Roman numerals have never had an official or widely recognized standard. In ancient Rome, use fluctuated widely, and in medieval times, it became completely chaotic. Even the reinstatement of a fully "classical" notation in the post-renaissance period failed to achieve entire uniformity; in fact, some current authors advocate different forms as providing more "flexibility."