The stories behind each day

Ancient Babylonians held new-year festivals over 4,000 years ago. In 46 BC Julius Caesar made January 1 the start of the year, named after Janus, the Roman god of beginnings. Today it is a time for fresh starts and resolutions.

Named after Saint Valentine, a Roman priest of the 3rd century. In the 1300s, the poet Chaucer linked the day with romantic love. By the 1800s people were exchanging handwritten cards, and it became a day to celebrate love and affection.

It grew from workers' movements in the early 1900s, with the first gatherings in 1911. The United Nations recognised it in 1977. It celebrates women's achievements and calls for equal rights.

Day and night are almost equal in length. For thousands of years, cultures have marked this moment as the return of light, new growth and planting season. Persian Nowruz, the new year, falls on this day.

First held in 1970 in the United States, when 20 million people took part in protecting the environment. It went global in 1990 and is now observed in over 190 countries.

It honours workers and remembers the 1886 Haymarket events in Chicago, when workers fought for an eight-hour working day. It is a public holiday in many countries, including Sri Lanka.

The longest day of the year. Ancient monuments such as Stonehenge line up with the sunrise on this day, and many cultures celebrate it with fires, music and midsummer festivals.

The United Nations declared this day in 2011 to encourage friendship between people, cultures and countries, and to build bridges of peace.

Day and night are equal again as the year turns towards winter. It has long been a time of harvest festivals and giving thanks for the year's crops.

It comes from Samhain, an ancient Celtic festival marking the end of harvest, when people believed spirits walked the earth. Costumes, carved pumpkins and trick-or-treating grew from these old traditions.

Set by the United Nations in 1954. It marks the date the UN adopted the Declaration of the Rights of the Child (1959) and the Convention on the Rights of the Child (1989).

The shortest day of the year, after which daylight starts to return. Many ancient festivals, such as the Roman Saturnalia and Yule, celebrated this rebirth of the sun.

Christians celebrate the birth of Jesus on this day, first recorded in Rome in 336 AD. Over time it gathered traditions such as decorated trees, gift-giving and Santa Claus, and is now enjoyed around the world.