Answer:
no one knows for sure but most think it was caused by WW2. When WWII started the USA started sending supplies to the allied powers and making the economy boom. When the USA entered the war millions of men where sent to the UK and all the jobs and factories where filled and pumping out supplies and resources at full swing.
It helped them develop a calendar. The stars were associated with their gods and horoscopes. In addition, they could create maps and a sense of direction
Japan<span>: Japan's Yamato dynasty traces its origins back to 660, making it the oldest continuous hereditary monarchy in the world. The 79-year-old Emperor Akihito has reigned since 1989 and is, according to legend, the 125th emperor in his line, though there's some debate as to the exact count of emperors</span>
