In countries which use the Gregorian calendar, New Year's Day is usually celebrated on 1 January. The order of months in the Roman calendar has been January to December since King Numa Pompilius in about 700 BC, according to Plutarch and Macrobius. However, Roman writers identified years by naming the year's consuls, who did not enter office on 1 January until 153 BC. Since then 1 January has been the first day of the year, except during the Middle Ages when several other days were the first (1 March, 25 March, Easter, 1 September, 25 December). With the expansion of Western culture to the rest of the world during the twentieth century, the 1 January date became global, even in countries with their own New Year celebrations on other days (e.g., China and India). At present, the celebration of the New Year is a major event worldwide. Many large-scale events are held in major cities around the world, with many large fireworks events on New Year's Eve (31 December). Sydney launched over 80,000 fireworks at midnight, and had more than one and a half million attendees; it was also the most-watched event on television worldwide last year. In Valparaiso upwards of two million visitors witnessed the largest fireworks display in a natural setting; a total of more than 21 kilometers of fireworks on the bay, from the commercial port city of Valparaiso to Concon, Chile, all in 25 minutes of entertainment. London's New Year celebrations centre around the London Eye, with an impressive fireworks display while Big Ben strikes midnight. In New York, the celebration is focused around a large crystal ball that descends in a one minute countdown in Times Square. Edinburgh plays host to one of the world's largest Hogmanay events. The celebrations last for four days and attract visitors from around the globe to take part in street parties and attend concerts. In the culture of Latin America there are a variety of traditions and superstitions surrounding these dates as omens for the coming year. January remains a symbol of the New Year's celebration. According to the Christian tradition, 1 January coincides with the circumcision of Christ (eight days after birth), when the name of Jesus was given to him (Luke 2: 21).

International Workers' Day (a name used interchangeably with may day) is a celebration of the social and economic achievements of the international labor movement. May Day commonly sees organized street demonstrations and street marches by millions of working people and their labour unions throughout most of the countries of the world.

The Communist Party of China (CPC), also known as the Chinese Communist Party (CCP), is the founding and the ruling political party of the People's Republic of China (PRC). It is the world's largest political party. While not a governing body recognized by the PRC's constitution, the CPC's position as the supreme political authority and power in the PRC is realized through its control of all state apparatuses and of the legislative process. The Communist Party of China was founded in May 1921 in Shanghai, and came to rule all of mainland China in 1949 after defeating its rival the Kuomintang (KMT) in the Chinese Civil War. The CPC claimed 75.93 million members[3] on 9 October 2009 which constitutes 5.6% of the total population of mainland China.

The Nanchang Uprising (simplified Chinese: 南昌起义; traditional Chinese: 南昌起義; pinyin: Nánchāng Qǐyì) (August 1, 1927) was the first major Kuomintang-Communist engagement of the Chinese Civil War, in order to counter the anti-communist purges by the Nationalist Party of China. The Kuomintang (KMT, or Nationalist Party) established a ‘Revolutionary Committee’ at Nanchang to plan the spark that was expected to ignite a wide-spread peasant uprising. Deng Yanda, Soong Qingling (Soong Ching-ling, Madame Sun Yat-sen) and Zhang Fakui (who later crushed the uprising) were among the political leaders. Military forces in Nanchang rebelled under the leadership of He Long and Zhou Enlai attempting to seize control of the city after the end of the first Kuomintang-Communist alliance. Other important leaders in this event were Zhu De, Ye Ting, and Liu Bocheng. Communist forces successfully occupied Nanchang and escaped from the siege of Kuomintang forces by August 5, withdrawing to the Jinggang Mountains of western Jiangxi. The day of August 1 was later regarded as the anniversary of the founding of the People's Liberation Army. It is regarded as the first action fought against the Kuomintang.

The National Day of the People's Republic of China (simplified Chinese: 国庆节; traditional Chinese: 國慶節; pinyin: guóqìng jié) is celebrated every year on October 1. It is a public holiday in the People's Republic of China to celebrate its national day. The PRC was founded on October 1, 1949 with a ceremony at Tiananmen Square. The Central People's Government passed the Resolution on the National Day of the People's Republic of China on December 2, 1949 and declared that October 1 is the National Day. The National Day marks the start of one of the two Golden Weeks in the PRC. However, there have been some recent controversies over whether Golden Weeks should be kept. The National Day is celebrated throughout mainland China, Hong Kong, and Macau with a variety of government-organised festivities, including fireworks and concerts. Public places, such as Tiananmen Square in Beijing, are decorated in a festive theme. Portraits of revered leaders, such as Sun Yat-sen, are publicly displayed.

Chinese New Year or Spring Festival is the most important of the traditional Chinese holidays. It is sometimes called the "Lunar New Year" by English speakers. The festival traditionally begins on the first day of the first month (Chinese: 正月; pinyin: zhēng yuè) in the Chinese calendar and ends on the 15th; this day is called Lantern Festival. Chinese New Year's Eve is known as Chúxī. It literally means "Year-pass Eve". Chinese New Year is the longest and most important festivity in the Lunar Calendar. The origin of Chinese New Year is itself centuries old and gains significance because of several myths and traditions. Ancient Chinese New Year is a reflection on how the people behaved and what they believed in the most. Celebrated in areas with large populations of ethnic Chinese, Chinese New Year is considered a major holiday for the Chinese and has had influence on the new year celebrations of its geographic neighbors, as well as cultures with whom the Chinese have had extensive interaction. These include Koreans (Seollal), Tibetans and Bhutanese (Losar), Mongolians (Tsagaan Sar), Vietnamese (Tết), and formerly the Japanese before 1873 (Oshogatsu). Outside of Mainland China, Hong Kong, Macau, and Taiwan, Chinese New Year is also celebrated in countries with significant Han Chinese populations, such as Singapore, Indonesia, Laos, Malaysia, the Philippines, and Thailand. In countries such as Australia, Canada and the United States, although Chinese New Year is not an official holiday, many ethnic Chinese hold large celebrations and Australia Post, Canada Post, and the US Postal Service issues New Year's themed stamps.