The 1970s

The decade the towers actually rose. Construction broke ground in August 1966, but the climb visible from the street, the part that shows up on film, happened as the 1970s opened: the North Tower topped out in December 1970, the South Tower in July 1971. For most of the decade, both stood at the same height with matching flat roofs. The lopsided silhouette most people picture when they think of the Twin Towers isn't quite accurate yet.

The complex was formally dedicated on April 4, 1973, though tenants had already been moving into the North Tower since 1970. The asymmetry (one tower topped with a broadcast antenna, one without) didn't arrive until right at the decade's end, when the North Tower's mast went up in 1979.