ISO-8601 Calendar

The ISO-8601 calendar is a system for organizing time that is widely used around the world. The calendar is based on the Gregorian calendar, but with a few key differences. The most notable difference is that the ISO-8601 calendar uses weeks that start on Monday, rather than Sunday. This makes it easier to compare dates across different cultures, as Monday is always the first day of the week. The ISO-8601 calendar is also used to define the week numbers. Each week is given a number, starting with the week that contains the first Thursday of the year. This makes it easy to calculate how many weeks have passed since a particular date. The ISO-8601 calendar is a useful tool for anyone who needs to work with dates from different cultures. It is also a helpful way to keep track of the passage of time.