The Klausjagen ("Nicholas chase") festival takes place in the Swiss town of Küssnacht on the eve of St. Nicholas Day. The image shows men wearing Iffelen or Infuln, which are enormous, incredibly ornate paper / wood hats which resemble a cross between a bishop's mitre and a stained glass window, lit from the inside by candles, and as much as seven feet tall. (Description from english Wikipedia article)