Walpurgis Night is a traditional Pagan holiday, Roman Catholic Saint's day, and Satanic  holiday celebrated on April 30 or May 1 in large parts of Central and Northern Europe
The current festival is in most countries celebrating it named after Saint Walpurga, born in Devonshire about 710. Due to her holy day falling on the same day, her name became associated with the celebrations. Walpurga was honored in the same way that Vikings had celebrated spring and as they spread throughout Europe, the two dates became mixed together and created the Walpurgis Night celebration. Early Christianity had a policy of 'Christianising' pagan festivals so it is perhaps no accident that St. Walpurga's day was set to May 1st
Historically Walpurgisnacht is derived from various Pagan spring customs. In the Norse tradition, Walpurgisnacht is considered the "Enclosure of the Fallen". It commemorates the time when Odin died to retrieve the knowledge of the runes, and the night is said to be a time of weakness in the boundary between the living and the dead. Bonfires were built to keep away the dead and chaotic spirits that were said to walk among the living then. This is followed by the return of light and the sun as celebrated during May Day.
Saint Walpurga herself was a niece of Saint Boniface and, according to legend, a daughter of the Saxon prince St. Richard. Together with her brothers she travelled to Franconia, Germany, where she became a nun and lived in the convent of Heidenheim, which was founded by her brother Willibald. Walpurga died of an illness shortly after moving the mortal remains of her brother , Saint Winibald on 25 February 779. She is therefore listed in the Roman Martyrology under 25 February. Her relics were transferred on 1 May such that she might be buried beside Willibald, and that day carries her name in, for example, the Finnish and Swedish calendars. .
In Germany, Walpurgisnacht (or Hexennacht, meaning Witches' Night), the night from April 30 to May 1, is the night when allegedly the witches hold a large celebration on the Blocksberg and await the arrival of Spring.
Walpurgis Night (in German folklore) the night of April 30 (May Day's eve), when witches meet on the Brocken mountain and hold revels with their gods..."
Brocken is the highest of the Harz Mountains of north central Germany. It is noted for the phenomenon of the Brocken spectre and for witches' revels which reputedly took place there on Walpurgis night.
The Brocken Spectre is a magnified shadow of an observer, typically surrounded by rainbow-like bands, thrown onto a bank of cloud in high mountain areas when the sun is low. The phenomenon was first reported on the Brocken.
—Taken from Oxford Phrase & Fable.
A scene in Goethe's Faust Part One is called "Walpurgisnacht", and one in Faust Part Two is called "Classical Walpurgisnacht".
In some parts of northern coastal regions of Germany, the custom of lighting huge Beltane fires is still kept alive, to celebrate the coming of May, while most parts of Germany have a derived Christianized custom around Easter called "Easter fires".
In rural parts of southern Germany it is part of popular youth culture to play pranks on Walpurgisnacht, e.g. tampering with neighbors' gardens, hiding possessions, or spraying graffiti on private property. These pranks occasionally result in serious damage to property or bodily injury.
Adolf Hitler, with several members of his staff (including Joseph Goebbels), committed suicide on Walpurgisnacht, April 30/May 1, 1945. Hitler was closely associated with the occult and mystical Thule Society. In the History Channel's documentary, Hitler and the Occult, author Dusty Sklar stated that "It's believed by some people that he chose April 30th deliberately because it coincided with Walpurgis Night, which is believed to be the most important date (along with Halloween) in Satanism . So according to one commentator he was giving himself up to the powers of darkness.". It was either that or giving himself up to the Soviet Army, which was approaching his location.
A large crowd, mostly students in typical Swedish white student caps, participating in the traditional Walpurgis Night celebration with song outside the Castle in Uppsala. The silhouette of the cathedral towers may be seen in the background. To the right are banners and standards of the student nations. Image from c. 1920.Walpurgis (sw: Valborgsmässoafton or Valborg) is one of the main holidays during the year in Sweden, alongside Christmas and Midsummer holiday. The forms of celebration in Sweden vary in different parts of the country and between different cities. One of the main traditions in Sweden is to light large bonfires, a custom which is most firmly established in Svealand, and which began in Uppland during the 18th century. An older tradition from Southern Sweden was for the younger people to collect greenery and branches from the woods at twilight, which were used to adorn the houses of the village. The expected reward for this task is to be paid in eggs.
The tradition which is most widespread throughout the country is probably singing songs of spring. Most of the songs are from the 19th century and were spread by students' spring festivities. The strongest and most traditional spring festivities are also found in the old university cities, like Uppsala and Lund where both current and graduated students gather at events that take up most of the day from early morning to late night on April 30, or "sista April" ("The last day of April") as it is called in Lund and elsewhere throughout the country. There are also newer student traditions like the carnival parade, The Cortège, which has been held since 1909 by the students at Chalmers in Gothenburg.
A team of students performing the traditional "capping of Havis Amanda" during Helsinki's Vappu.Today in Finland, Walpurgis Night (Vapunaatto, Valborgsmässoafton) is, along with New Year's Eve and Juhannus, the biggest carnival-style festivity that takes place in the streets of Finland's towns and cities. The celebration is typically centered on plentiful use of sparkling wine and other alcoholic beverages. The student traditions are also one of the main characteristics of "Vappu". From the end of the 19th century, "Fin de Siècle", and onwards, this traditional upper class feast has been co-opted by students attending university, already having received their student cap. Many people who have graduated from lukio wear the cap. One tradition is drinking sima, whose alcohol content varies. Fixtures include the capping of the Havis Amanda, a nude female statue in Helsinki, and the biannually alternating publications of ribald matter called Äpy and Julkku. Both are sophomoric; but while Julkku is a standard magazine, Äpy is always a gimmick. Classic forms have included an Äpy printed on toilet paper and a bedsheet. Often the magazine has been stuffed inside standard industrial packages such as sardine-cans and milk cartons. The festivities also include a picnic on May 1st, which is sometimes prepared in a lavish manner.
The Finnish tradition is also a shadowing of the Socialist May Day parade. Expanding from the parties of the left, the whole of the Finnish political scene has adopted Vappu as the day to go out on stumps and agitate. This does not only include center and right-wing parties, but also other insititutions like the church have followed suit, marching and making speeches. In Sweden it is only the left-wing parties which use May 1 for political activities, while others observe the traditional festivities. Left-wing activists who were active in the 1970s still party on May Day. They arrange carnivals and the radio plays old leftist songs from the 1970s.
The First of May is also a day for everything fun and crazy: children and families gather in market places to celebrate the first day of the spring and the coming summer. There are balloons and joy, people drink their first beers outside, there are clowns and masks and a lot of fun. The first of May includes colourful streamers, funny and silly things and sun. The first of May means the beginning of the spring for many people in Finland. There is also an erotic frisson involved with Vappu's ribald side. The only semi-humorous adage is that one who doesn't have a romantic partner on Vappu will have to make do without one also on midsummer night.
Traditionally May 1st is celebrated by a picnic in a park (Kaivopuisto or Kaisaniemi in the case of Helsinki). For most, the picnic is enjoyed with friends on a blanket with good food and sparkling wine. Some people, however, arrange extremely lavish picnics with pavilions, white table cloths, silver candelabras, classical music and lavish food. The picnic usually starts early in the morning, and some hardcore party goers continue the celebrations of the previous evening without sleeping in between. Some Student organisations have traditional areas where they camp every year and they usually send someone to reserve the spot early on. As with other Vappu traditions, the picnic includes student caps, sima, streamers and balloons.
In Estonia, Volbriöö is celebrated on the night from April 30 to May 1, with the following day (May 1) being a public holiday of lesser importance called "Spring Day" (Kevadpüha). Yet Volbriöö itself has considerable importance as one of the main reasons to party across the country. Influenced by German culture, the night originally stood for the gathering and meeting of witches. Nowadays some people still dress up as witches and wander the streets in a carnival-like mood.
Yet for most Estonians, Volbriöö has become a reason to celebrate the arrival of Spring with huge outdoor drinking and partying throughout the night. This is especially strongly honoured in Tartu, the university town in Southern Estonia. For Estonian students in student corporations (fraternities and sororities), the night starts with a traditional march on the streets of Tartu, followed by visiting of each others' corporation houses all night, drinking lots of beer as they stay with the hosts and move along the streets from one place to another. The following day (May 1) is known as Kaatripäev (Hangover Day, derived from the German word 'Kater' meaning 'Hangover').
 Satanic observences
As a night when magical powers are supposedly heightened, various occultists have celebrated Walpurgis Night in the various ways described above. Witches' covens have traditionally held the night sacred. It is thus one of the three holidays recognized by Anton LaVey's Church of Satan. In addition to the occult significance the date carries, it also marks the formation of the Church of Satan in the year 1966, or I Anno Satanas. This date is commonly celebrated by Satanists with private or group rituals, and private parties or family celebrations to commemorate the foundation of the Church.