Mediator Dei §132

¹³² Now, the Church in the course of centuries has introduced various forms of this worship which are ever increasing in beauty and helpfulness: as, for example, visits of devotion to the tabernacles, even every day; benediction of the Blessed Sacrament; solemn processions, especially at the time of Eucharistic Congress, which pass through cities and villages; and adoration of the Blessed Sacrament publicly exposed. Sometimes these public acts of adoration are of short duration. Sometimes they last for one, several and even for forty hours. In certain places they continue in turn in different churches throughout the year, while elsewhere adoration is perpetual day and night, under the care of religious communities, and the faithful quite often take part in them.