It's easy to understand why these ferry riders were so captivated by the Twin Towers, which were almost completely built at the edge of Lower Manhattan when they took this trip crossing New York Harbor. (No antenna yet on the roof of the North Tower; that would come in 1978.)

This photo, by Morris Huberland and part of the Morris Huberland Collection in the NYPL Digital Collection, must have been taken in the early 1970s.

It's quiet and contemplative, reflecting the tone many New Yorkers will take on this week as the 20th anniversary of 9/11 approaches.