There is an old catholic tradition of building and maintaining a "May altar" dedicated to Our Lady throughout the month of May. The photographs of these May Altars come from the home of my brother, Fr. Robert-James, OPC. The following excerpt comes from the webpages of The Marian Library/The International Marian Research Institute in Dayton, OH.
To the specific characteristics of the May devotion is to be counted the specially set up May altar - be it as an addition to or specially decorated altar in the church or as a "house altar" in the family circle. Like the May devotions themselves, the custom to highlight this type of May altar stems from southern European countries. A report from France in 1842 speaks of Our Lady's altar in May showing off in rich splendor, while the families also erected and decorated small home altars.