The document discusses the history and development of pi. Pi is the mathematical constant that represents the ratio of a circle's circumference to its diameter. Ancient civilizations like Egypt and Greece were aware of pi as a constant ratio slightly higher than 3. Archimedes calculated pi more accurately in ancient Greece. Over centuries, mathematicians have calculated pi to increasing numbers of decimal places. Pi is ubiquitous in formulas used by many fields like engineering and has no discernible pattern in its decimal representation.