The Taliban on Tuesday celebrated the departure of U.S. military forces by shooting in the air at the Kabul airport and declaring victory. Video footage posted online showed members of the Taliban, designed by many federal agencies as a terrorist organization, entering the airport armed with U.S. rifles and gear. It came just moments after the Americans carried out their final evacuation flight, with the U.S. Central Command’s Gen. Frank McKenzie announcing the official end of the 20-year-long conflict. “It is a historical day and a historical moment,” Taliban spokesman Zabihullah Mujahid told a news conference at the airport, according to the Reuters news agency. “We are proud of these moments, that we liberated our country from a great power.” Known as the “graveyard of empires” by some, Afghanistan has been a notoriously difficult region to conquer and control. The Soviet Union waged a war for years in the 1980s …