Shadows of the Past, explores the forces that shaped the city in the second half of the 20th century, as New York plunged into the most threatening period of decline and disorder in its history—only to rise again, thanks to a stunning drop in crime, to regain its place at the vanguard of world cities. The episode concludes in the summer of 2001, with New York, now remarkably safe and secure, unaware that a new threat from beyond its borders would soon threaten to undo all the progress of the previous decade.