eiffel tower

I've got interested, since I am going with about 10 of my students to Paris for the Euromech conference I am coorganizing in July, by the design of the Eiffel Tower.  Eiffel was a great engineer, and indeed his shape of the tower apparently comes from his ingenious idea of  balancing weigth and wind pressure so that there is little need of foundations.  WIKIPEDIA has an account of this design idea, and the resulting integro-differential equation.