The Empire State Building was designed and constructed in an incredibly short length of time. And I think it's a real tribute both to the architecture and the engineering and the people who financed it, and the city of New York, for that matter. It's a magnificent building. It's entirely different -- in terms of my work, the structural work -- from the World Trade Center.

For example, it has in it a steel frame. But that steel frame was designed to carry all of the loads that the designers thought would be on the building. They were wrong by a significant margin, in terms of the magnitude of the loads. But they created their design based on experience in the past. And so even though the steel frame was in fact not adequate to carry the loads that would in fact go on the building, the system -- which consisted of the steel frame and all of the masonry in the building -- was quite strong enough to do the job.

The two buildings (Empire State and World Trade Center) were in one way the same, in that they were symbolic of the city of New York. But inside , inside of the guts of it, if you will, the structure, entirely different. Entirely different buildings.

And all of the work that had been done from the Thirties -- stopped with the Second World War and picked up again -- basically was built on that technology. Remember, the engineers did not even have computers. They used slide rules. I knew how to use a slide rule. Bet I did. But I'm sure that there was no engineer in New York City that had a computer, except us. We were the only ones. We were the only ones who knew how to use it, even. We were, in a sense, many steps ahead of the rest of the profession.