The first day of the week varies all over the world. In most cultures, Sunday is regarded as the first day of the week although many observe Monday as the first day of the week. According to the Bible, the Sabbath or Saturday is the last day of the week which marks Sunday as the first day of the week for many Jewish and Christian faiths, while many countries regard Monday as the first day of the week.
According to the international standard ISO 8601, Monday is the first day of the week ending with Sunday as the seventh day of the week. Although this is the international standard, countries such as the United States still have their calendars refer to Sunday as the start of the seven-day week.