As an architecture and city lover, it’ll probably surprise you that I’ve never been to Chicago. I think it may have to do with the fact that it has always felt like a sister to Toronto–another Great Lakes city of comparable size. And when you travel, you often want something novel.

But that’s no excuse. 

Thankfully I’m happy to report that last week I booked a trip to Chicago for this August. I’ll be there for an extended long weekend. But since it’s for a bachelor party, it remains to be seen how much archi-touring I’ll actually get a chance to do.

Chicago is a hugely important city in the world of architecture and city building. From Frank Lloyd Wright to Mies van der Rohe to Louis Sullivan, the city has deep architectural roots.

When most people think of skyscrapers they think of New York. But in actuality, if there’s one city that gave birth to the modern skyscraper I would argue that it was Chicago. And it was made possible by the steel industry.

Before the late 19th century, tall buildings were largely built with their exterior walls supporting most of the loads. This meant that the taller you went, the thicker the walls had to be near the bottom of the building. This is why older buildings often feel so heavy and permanent.

But when structural steel became widely available, a new building form was created. All of a sudden architects and builders could create relatively light weight structural steel frames to support the building. The skin, or outside of the building, was no longer carrying the weight.

That made images like this possible:

For most of us today, this building under construction looks fairly typical. First the structure goes up and then it gets clad with its window and exterior skin. But at the time, this sort of construction technique–with the 3rd and 4th floors still unenclosed and the upper floors finished–would have blown people’s minds. It was an entirely new way of building.

Steel framed buildings removed the technical limitations of building tall and also opened up entirely new possibilities for architectural expression–such as the all glass building. Today, there’s a lot of criticism around our glass buildings. But it’s interesting to note that it started as the futuristic dream of architects.

Freed from the technical limitations of load-bearing exterior walls, architects such as Mies van der Rohe began dreaming of transparent, all glass buildings. For them it represented modernity. It was the future. Above is an early charcoal sketch of that dream by Mies.

But our fixation with glass and transparency has never been because of environmental efficiency. It was about light, transparency and feelings of modernity. So as sustainability becomes increasingly critical, we should remember that there’s still lots of innovating left for us to do.

Art and architecture has always been a representation of the time and era in which it was created–which is one of the reasons I’m so interested in technology today. It’s our era. It’s our “structural steel”. And it’s going to impact our cities.

When posterity looks back on us and what we’ve done, I’m sure that will be clear.