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).

The Preliminary Treaty of San Stefano (Turkish: Yeşilköy Anlaşması) was a treaty between Russia and the Ottoman Empire signed at the end of the Russo-Turkish War, 1877–78. It was signed on March 3, 1878 at San Stefano (now Yeşilköy), a village west of Istanbul, by Count Nicholas Pavlovich Ignatiev and Alexander Nelidov on behalf of the Russian Empire and Foreign Minister Safvet Pasha and Ambassador to Germany Sadullah Bey on behalf of the Ottoman Empire. Although according to the official Russian position, by signing the treaty, Russia had never been intended to anything more than a temporary rough draft, so to enable a final settlement with the other Great Powers, this preliminary treaty almost immediately became the central point of Bulgarian foreign policy, lasting until 1944 and leading to the disastrous Second Balkan War and Bulgaria's even more disastrous participation in World War I. The treaty provided the creation of a Principality of Bulgaria as autonomous, after almost 500 years of Ottoman domination. March 3, the day the treaty was signed, is celebrated as Liberation Day in Bulgaria. However, the enlarged Bulgaria envisioned by the treaty alarmed neighboring states as well as France and Great Britain. As a result, it was never implemented, being superseded by the Treaty of Berlin following the Congress of the same name.

International Women's Day (IWD) is marked on March 8 every year. It is a major day of global celebration for the economic, political and social achievements of women. Started as a political event, the holiday blended in the culture of many countries (primarily Russia and the countries of former Soviet bloc). In some celebrations, the day lost its political flavour, and became simply an occasion for men to express their love to the women around them in a way somewhat similar to Mother's Day and St Valentine's Day mixed together. In others, however, the political and human rights theme as designated by the United Nations runs strong, and political and social awareness of the struggles of women worldwide are brought out and examined in a hopeful manner.

Good Friday, also called Holy Friday, Black Friday, or Great Friday, is a holiday observed primarily by adherents to Christianity commemorating the crucifixion of Jesus and his death at Calvary. The holiday is observed during Holy Week as part of the Paschal Triduum on the Friday preceding Easter Sunday, and often coincides with the Jewish observance of Passover. Based on the scriptural details of the Sanhedrin Trial of Jesus, the Crucifixion of Jesus was most probably on a Friday. The estimated year of Good Friday is AD 33, by two different groups, and originally as AD 34 by Isaac Newton via the differences between the Biblical and Julian calendars and the crescent of the moon. A third method, using a completely different astronomical approach based on a lunar Crucifixion darkness and eclipse model (consistent with Apostle Peter's reference to a "moon of blood" in Acts 2:20) arrives at the same date, namely Friday April 3, AD 33.

Easter (Greek: Πάσχα) is the most important annual religious feast in the Christian liturgical year. According to Christian scripture, Jesus was resurrected from the dead on the third day of his crucifixion. Christians celebrate this resurrection on Easter Day or Easter Sunday (also Resurrection Day or Resurrection Sunday), two days after Good Friday and three days after Maundy Thursday. The chronology of his death and resurrection is variously interpreted to be between AD 26 and AD 36. Easter also refers to the season of the church year called Eastertide or the Easter Season. Traditionally the Easter Season lasted for the forty days from Easter Day until Ascension Day but now officially lasts for the fifty days until Pentecost. The first week of the Easter Season is known as Easter Week or the Octave of Easter. Easter also marks the end of Lent, a season of fasting, prayer, and penance. Easter is a moveable feast, meaning it is not fixed in relation to the civil calendar. The First Council of Nicaea (325) established the date of Easter as the first Sunday after the full moon (the Paschal Full Moon) following the vernal equinox. Ecclesiastically, the equinox is reckoned to be on March 21. The date of Easter therefore varies between March 22 and April 25. Eastern Christianity bases its calculations on the Julian Calendar whose March 21 corresponds, during the twenty-first century, to April 3 in the Gregorian Calendar, in which calendar their celebration of Easter therefore varies between April 4 and May 8. Easter is linked to the Jewish Passover not only for much of its symbolism but also for its position in the calendar. Relatively newer elements such as the Easter Bunny and Easter egg hunts have become part of the holiday's modern celebrations, and those aspects are often celebrated by many Christians and non-Christians alike.

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.

Day of the Bulgarian Army.

Celebrating Bulgarian culture and the Cyrillic alphabet.

Remembering the unification of Bulgaria and Eastern Rumelia (1885).

The independence of Bulgaria from the Ottoman Empire was proclaimed on 5 October [O.S. 22 September] 1908 in the old Bulgarian capital Tarnovo by Prince (Knyaz) (afterwards Tsar) Ferdinand of Bulgaria. Bulgaria has been Europe's tenth oldest country by continuous sovereignty since that date.

Christmas Eve is the day before Christmas Day, a widely celebrated holiday commemorating the birth of Jesus of Nazareth. It is a culturally significant celebration for most of the Western world and is widely observed as a full or partial holiday in anticipation of Christmas. In Western culture, Christmas Eve is celebrated on December 24. However, the Coptic, Serbian, Russian, Macedonian, and Georgian Orthodox Churches, as well as the Greek Orthodox Church of Jerusalem, use the Julian calendar, which is currently thirteen days behind the Gregorian calendar, so Christmas Eve for the adherents of those Churches coincides with January 6 of the following year in the Gregorian calendar.

Christmas or Christmas Day is an annual Christian holiday commemorating the birth of Jesus Christ. It is celebrated on December 25, but this date is not known to be Jesus' actual birthday, and may have initially been chosen to correspond with either the day exactly nine months after some early Christians believed Jesus had been conceived, a historical Roman festival, or the date of the northern hemisphere's winter solstice. Christmas is central to the Christmas and holiday season, and in Christianity marks the beginning of the larger season of Christmastide, which lasts twelve days

Boxing Day is a bank and public holiday commonly occurring on the 26th of December. It is observed in the United Kingdom, Australia, Canada, Ghana, Switzerland, Germany, Greenland, Netherlands, New Zealand, Hong Kong, Nigeria,Kenya, Guyana, Trinidad & Tobago, Jamaica and countries in the Commonwealth of Nations with a mainly Christian population. In South Africa this public holiday is now known as the Day of Goodwill. Though it is not an official holiday in the United States, the term "Boxing Day" is used by some Americans, particularly those that live near the Canada – United States border. In Canada, Boxing Day is listed in the Canada Labour Code as a holiday. It is not an official holiday in Quebec or British Columbia. The traditional recorded celebration of Boxing Day has long included giving money and other gifts to those who were needy and in service positions. The European tradition has been dated to the Middle Ages, but the exact origin is unknown and there are some claims that it goes back to the late Roman/early Christian era; metal boxes were placed outside churches used to collect special offerings tied to the Feast of Saint Stephen. In the United Kingdom it certainly became a custom of the nineteenth century Victorians for tradesmen to collect their "Christmas boxes" or gifts in return for good and reliable service throughout the year on the day after Christmas. However, the exact etymology of the term "Boxing" is unclear, with several competing theories, none of which is definitively true. Another possibility is that the name derives from an old English tradition: in exchange for ensuring that wealthy landowners' Christmases ran smoothly, their servants were allowed to take the 26th off to visit their families. The employers gave each servant a box containing gifts and bonuses (and sometimes leftover food). In addition, around the 1800s, churches opened their alms boxes (boxes where people place monetary donations) and distributed the contents to the poor.