Speaking of bridge collapses, there's everyone's favorite suspension bridge - the first Tacoma Narrows bridge. http://www.pontifex2.com/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'> Refer to discussions of new materials and heavy cable to support stiffening trusses. Perhaps Callis' delicate solution to the torsion problem would make suspension bridges work better.