Have you ever felt annoyed by the fact that national holidays in your country are often religious holidays? In many European countries Epiphany, Good Friday, Easter Monday, Ascension Day, Whit Monday, Assumption, All Saints' Day, Christmas and/or St Stephens' Day (aka Boxing Day in the UK) are public holidays. Some countries have additional saints' day as holidays, such as some Spanish regions.

That does not make sense in a modern secular and/or pluralistic society. According to a recent Pew Research survey, only 18% of Western, Central and Northern Europeans are practising Christians, against 24% of unaffiliated and 46% of non-practising Christians (i.e. Christian by tradition, not by religious conviction). Add to this that 5% of Europeans belong to other religions altogether.

There are already a few secular holidays, like New Year's Day, Labour Day, Armistice Day or the country's national day. Europe Day also exists in all the EU (9th May) but is not an official holiday anywhere yet. Overall the holiday calendar is largely dominated by Christian holidays in a society where less than 1 in 5 person is a practising Christian. It's time to reform this in a more meaningful way. Here are a few suggestions based on important days that marked the history of science, and without which modern society wouldn't exist as we know it.

- 7th April : World Health Day already exists as a global health awareness day under the sponsorship of the World Health Organization (WHO), as well as other related organizations. Its impact would be greater if it were to become a national holiday.

- 22nd April : Earth Day is an annual event celebrated on April 22. Worldwide, various events are held to demonstrate support for environmental protection. First celebrated in 1970, Earth Day now includes events in more than 193 countries, which are now coordinated globally by the Earth Day Network

- 25th April : DNA Day originated in the USA in 2003. According to Wikipedia it commemorates the day in 1953 when James Watson, Francis Crick, Maurice Wilkins, Rosalind Franklin and colleagues published papers in the journal Nature on the structure of DNA. Furthermore, on that day in 2003 it was declared that the Human Genome Project was very close to complete, and "the remaining tiny gaps [we]re considered too costly to fill."

- 5th July : Publication of newton's PhilosophiƦ Naturalis Principia Mathematica, the book which laid the ground to classical physics. One way of naming it could be 'Physics Day'.

- 15th August : Already a national holiday in traditionally Catholic countries (Feast of the Assumption of Mary) as well as in Greece and Cyprus (Dormition of the Theotokos), this date should be rather remembered as the end of WWII like it already is in the UK, USA and Japan.

- 10th October : Metric Day to celebrate the metric system, also known as the International System of Units, which has been adopted by every country in the world (except for non-scientists in the USA). As it is based on decimalisation, it should appropriately be celebrated on 10/10.

- 29th October : Internet Day is already celebrated in many Latin American countries since 2005. Shortly afterwards, at the Summit of the Information Society celebrated in Tunisia in November 2005, it was decided to propose to the UN the designation of October 29 as the World-wide Day of the Information Society, which resulted in Internet Day being celebrated on that day.

- 1st November : This day is already a national holiday in many historical Catholic countries as All Saints' Day. But secular Europeans might prefer to celebrate the creation of the European Union when the Maastricht Treaty came into force on 1st November 1993, thus removing borders between member states and creating a European citizenship.

- 24th November : Publication of Darwin's Origins of Species, possibly the most important book in the history of biology. It could be called 'Evolution Day'.

- 25th November : Publication of Einstein's general theory of relativity, which ushered in the age of modern physics, including the Big Bang Theory, the existence of black holes, the spacetime continuum and the dawn of the atomic age. It could be called 'Relativity Day'.