Allied military intelligence indicated Adolf Hitler had built an underground Alpine fortress to house “the elite of Nazi Germany” in a desperate, final stand in World War II, according to documents released today.

Intelligence reports from 1944 and 1945, the last two years of the war, suggested that leading Nazis would seek refuge from an allied invasion of Germany in a vast underground network of tunnels and caves in a “Nazi National Redoubt” hidden within the Austrian Alps, the secret files published by the U.K.’s National Archives in London showed....