In the Gregorian calendar, New Year's Eve refers to the evening, or commonly the entire day, of the last day of the year, 31 December, also known as Old Year's Day. In many countries, New Year's Eve is celebrated with dancing, eating, drinking, and watching or lighting fireworks. Many Christians attend a watchnight service to mark the occasion. New Year's Eve celebrations generally continue into New Year's Day, 1 January, past midnight.