The inventor of the watch is considered to be Peter Henlein, who in 1504 placed the spring mechanism that drives the clock in a “portable” box, creating the first pocket watch. This type of watch was most popular until World War I. Peter Henlein was a watchmaker from Nuremberg, and the first watches resembled large chicken eggs in shape, which is why they were called Nuremberg eggs. ¹⁾

Time zones extend from UTC-12 to UTC+14, covering a total of 26 hours of stretch. This means that there are areas (in Oceania) that have the same time but different dates, depending on their political affiliation: Hawaii (date aligned with the US) has the same local time as the Baker Islands (date aligned with Oceania). ²⁾

Ming (c. 1499-2006) is an Icelandic cyprinid clam caught near Iceland in 2006. Ming's age is estimated at 507 years. It was the longest-lived known single animal whose age was estimated with a high degree of accuracy. The age of clams is estimated much like the age of trees by counting the “rings” on their shells. Once the age of the clam was determined, it was jokingly named “Ming,” a name derived from the Chinese Ming dynasty that ruled China at the time the animal was born. ³⁾

The Gregorian calendar was introduced in 1582 by Pope Gregory XIII. It corrected the shift of the actual date of the beginning of spring from the Julian calendar and introduced the principle that years with numbers divisible by 100, but not divisible by 400, are not leap years. Therefore, the difference between the calendars is the number of leap years over 400 years. ⁴⁾

There was no zero year - the year 1 BC was immediately followed by 1 AD. Therefore, the year numbers of different eras cannot simply be subtracted as if they were integers.⁵⁾