Battle of Dybbøl Day is observed in Denmark every April 18, commemorating the anniversary of the Battle of Dybbøl, a significant conflict in the Second Schleswig War fought in 1864. This day serves as a flag-flying day for the Danish military and is primarily a solemn memorial day, particularly recognized within military circles. The battle marked a decisive defeat for Denmark against Prussian forces, which ultimately influenced the outcome of the war and led to Denmark ceding the Duchies of Schleswig, Holstein, and Saxe-Lauenburg. On this date, a national memorial is typically held in Dybbøl, attended by soldiers of the Royal Danish Army dressed in period uniforms, honoring the historical significance of the event.