Today is May Day, and historically, May Day was celebrated to welcome the spring. People used to celebrate the day with a Maypole, in which colorful ribbons and flowers decorated a pole and people danced and sang. Also, May Day baskets can occasionally be found on the doorsteps, anonymously left for friends and neighbors.
Norma Lindeen at the Swedish Heritage Museum explains that something similar to a Maypole is used in their festivities in June, because in Sweden they celebrate the first day of summer. This year their celebration will be held on June 25th.