The origin of the May Day as a day for celebration dates back to the days, even before the birth of Christ. And like many ancient festivals it too has a Pagan connection.
For the Druids of the British Isles, May 1 was the second most important holiday of the year. Because, it was when the festival of Beltane held. It was thought that the day divides the year into half. The other half was to be ended with the Samhain on November 1. Those days the May Day custom was the setting of new fire. It was one of those ancient New Year rites performed throughout the world. And the fire itself was thought to lend life to the burgeoning springtime sun. Cattle were driven through the fire to purify them. Men, with their sweethearts, passed through the smoke for seeing good luck.
Then the Romans came to occupy the British Isles. The beginning of May was a very popular feast time for the Romans. It was devoted primarily to the worship of Flora, the goddess of flowers. It was in her honor a five day celebration, called the Floralia, was held. The five day festival would start from April 28 and end on May 2. The Romans brought in the rituals of the Floralia festival in the British Isles. And gradually the rituals of the Floralia were added to those of the Beltane. And many of today’s customs on the May Day bear a stark similarity with those combined traditions.
May day observance was discouraged during the Puritans. Though, it was relived when the Puritans lost power in England, it didn’t have the same robust force. Gradually, it came to be regarded more as a day of joy and merriment for the kids, rather than a day of observing the ancient fertility rights.

The tradition of Maypole and greeneries:
By the Middle Ages every English village had its Maypole. The bringing in of the Maypole from the woods was a great occasion and was accompanied by much rejoicing and merrymaking. The Maypoles were of all sizes. And one village would vie with another to show who could produce the tallest Maypole. Maypoles were usually set up for the day in small towns, but in London and the larger towns they were erected permanently.
The Maypole tradition suffered a setback for about a couple of decades since the Puritan Long Parliament stopped it in 1644. However, with the return of the Stuarts, the Maypole reappeared and the festivities of May Day were again enjoyed. One of the great Maypoles, was
The changes brought about by the Reformation included attempts to do away with practices that were obviously of pagan origin. But the Maypole, or, May tree, was not issued in practice at the behest of the second Stuart.
Although they succeeded in doing this, Maypole with most of the other traditions, many still survived. And Maypole is one of them. In France it merely changed its name. In Perigord and elsewhere, the May Tree became the “Tree of Liberty” and was the symbol of the French Revolution. Despite the new nomenclature, the peasants treated the tree in the same traditional spirit. And they would dance around it the same way as their forefathers had always done.

Maypoles and trees:
Trees have been linked to a part of celebration, perhaps, to the days ancient New Year rites. The association of trees to this celebration has come riding on the back of the spring festival in ancient Europe. Trees have always been the symbol of the great vitality and fertility of nature and were often used at the spring festivals of antiquity. The anthropologist E. O. James finds a strong relationship between the ancient tree related traditions of the British and the Romans. According to James’ description, as a part of the May Day celebration, the youths in old Europe cut down a tree, lopped off the branches leaving a few at the top. They then wrapped it round with violets like the figure of the Attis, the ancient Roman god. At sunrise, they used to take it back to their villages by blowing horns and flutes. In a similar manner, the sacred pine tree representing the god Attis was carried in procession to the temple of Cybele on Rome’s Palatine Hill during the Spring Festival of March 22.

Roots of May Day celebration in America:
The Puritans frowned on May Day, so the day has never been celebrated with as much enthusiasm in the United States as in Great Britain. But the tradition of celebrating May Day by dancing and singing around a maypole, tied with colorful streamers or ribbons, survived as a part of the English tradition. The kids celebrating the day by moving back and forth around the pole with the the streamers, choosing of May queen, and hanging of May baskets on the doorknobs of folks — are all the leftovers of the old European traditions.

May Day around the World.
May Day (May 1st) is celebrated in many places around the world. The traditions and stories surrounding May Day vary from place to place. There is, however, one thing that is similar in most celebrations – the use of Flowers!
One of the most popularly known May Day traditions is to hang a basket full of spring flowers and/or other small gifts on a neighbor’s doorknob. The trick is you don’t want the neighbor to see you! If you get caught, you are supposed to get a kiss.
In London, May Day is celebrated with the children going from house to house. They bring flowers and get pennies in return. The pennies are then thrown into a wishing well. The pennies are then donated to charity.
In France, cows play an important role in May Day. The cows are led in parades with many flowers attached to their tails. The people watching the parade try to touch the cows; it is believed to be good luck.
In Germany, one tradition is for boys to secretly plant a May tree in front of the window of the girl they love.
On May 1st, people in Hawaii celebrate their own version of May Day; they call it Lei Day. People give Hawaiian leis to each other. They put them around each other’s necks and sometimes give a traditional kiss.