天上人间双响炮是什么意思

　　Little-known chapters of American history are explored, involving the CIA, African Americans in the Wild West, a scrapped naval super weapon, and more. 　　S3 E1 - The Osage Murders 　　S3 E2 - Birth of Shadow Ops 　　S3 E3 - Forged in Slavery 　　S3 E4 - CIA Museum Declassified