11.   They have also noted that the towers remained standing after the initial impacts, almost certainly saving thousands of lives.

12.   They will then vary parameters in the computer model, like better fireproofing or thicker columns, that perhaps could have lengthened how long the towers remained standing.

13.   Michele Jamialkowski, the head of an international committee organized to save the tower, said that all goes as planned, the tower should remain stable for centuries.

14.   After that delay climbers worked with added haste and by Wednesday only the four corner towers remained to be covered.