The last century offers countless examples of how one might treat a great monument destroyed by war. One might repair and rebuild it (as was done with the Benedictine abbey of Monte Cassino), preserve it as a ruin (Coventry Cathedral), or even replace it with a scrupulous facsimile (the Frauenkirche in Dresden). Where there is will, knowledge, and energy, there is little that cannot be done; the destroyed city of Warsaw was practically reassembled from the ground up in the wake of World War II. Then why has it been so difficult to replace the twin towers of the World Trade Center? Four years after the attacks of 9/11—four years of design competitions, planning studies, and public forums—the design that has emerged is an unlovely and unloved fortress of a skyscraper, which seems to inspire no emotion deeper than a kind of resigned chagrin. This was to have been the building of the century: what ...