Standing on the banks of New York Harbor near the Staten Island Ferry terminal is Postcards, a pair of 30-foot-tall white marble wing sculptures that frame lower Manhattan. Designed by New York architect Masayuki Sono and built in 2004, the memorial honors 274 Staten Islanders: those killed at the World Trade Center, one passenger killed when United Airlines Flight 93 crashed in Shanksville, Pa., and a resident killed in the 1993 World Trade Center bombing.