The Norwegian Flag is seen everywhere in Norway and even Norwegians abroad wave the flag on the 17 of May
Norwegian Constitution Day is the National Day of Norway and is an official national holiday observed on May 17 each year. Among Norwegians, the day is referred to simply as syttende mai (meaning May Seventeenth), Nasjonaldagen (The National Day) or Grunnlovsdagen (The Constitution Day), although the latter is less frequent.
17th of May 1893 by Norwegian painter Christian Krohg (1852–1925). Note that the flag does not have the Union badge of Norway and Sweden, the so-called sildesalaten (Herring salad).
The Constitution of Norway was signed at Eidsvoll on May 17 in the year 1814. The constitution declared Norway to be an independent nation.
The celebration of this day began spontaneously among students and others from early on. However, Norway was at that time under Swedish rule (following the Convention of Moss in August 1814) and for some years the King of Sweden and Norway was reluctant to allow the celebrations. For a couple of years in the 1820s, King Karl Johan actually forbade it, as he thought the celebrations a kind of protest and disregard—even revolt—against Swedish sovereignty. The king’s attitude changed slightly after the Battle of the Square in 1829, an incident which resulted in such a commotion that the king had to allow it. It was, however, not until 1833, that anyone ventured to hold a public address on behalf of the day. That year, official celebration was initiated by the monument of the late politician Christian Krohg, known to have stopped the king from gaining too much personal power. The address was held by Henrik Wergeland, thoroughly witnessed and accounted for by a Swedish spy, sent by the king himself.
After 1864 the day became more established when the first children’s parade was launched in Christiania, at first consisting only of boys. This initiative was taken by Bjørnstjerne Bjørnson, although Wergeland made the first known children’s parade at Eidsvoll around 1820. It was only in 1899 that girls were allowed to join in the parade for the first time.
By historical coincidence, the Second World War ended in Norway nine days before that year’s Constitution Day, on May 8, 1945, when the occupying German forces surrendered. Even if The Liberation Day is an official flag day in Norway, the day is not an official holiday and is not broadly celebrated. Instead a new and broader meaning has been added to the celebration of Norwegian Constitution Day on May 17.
The day focused originally on the Norwegian constitution, but after 1905, the focus has been directed also towards the royal family.
Read more about the 17 of May here: Wikipedia