STOCKHOLM (AP) — Sweden will honor its World War II hero Raoul Wallenberg with an annual commemoration day in recognition of his achievements in saving thousands of Jews from the Nazis in Hungary.

Wallenberg, who would have turned 100 this year, was on a diplomatic mission in Hungary when detained by Soviet authorities in 1945. He is believed to have died in captivity, though the time and circumstances of his death remain a mystery.

Wallenberg is credited for saving at least 20,000 Jews by giving them Swedish travel documents, or moving them to safe houses. He was also instrumental in dissuading German officers from massacring the 70,000 inhabitants of Budapest’s ghetto.

Swedish Culture Minister Lena Adelsohn Liljeroth said Friday that the country will earmark Aug. 27 as an official Wallenberg day.