Newbie Nugget: Three Centuries in One View

I'm not sure if I've mentioned it more than 100 times, but I've become an architecture geek since moving to Chicago. If you spend a few hours wandering the Loop, you'll find it incredibly easy to understand why. 
The architecture in this city is stunning.
It's diverse, it's eye catching, it's exciting and there are so many interesting stories and anecdotes behind each of the buildings.
3 Century View
This weekend, I took another architecture boat tour. Yes, that's my second boat tour this summer. No, I do not consider that overkill. Yes, if you'd like someone to accompany you on one next weekend, I'll be happy to go again.
On the tour, our guide pointed out this three century view just hanging out and begging to have its picture taken. 
Here are the details:
a. The Riverbend Building: construction on this primarily residential building was completed in 2002
b. The Fulton House: construction on this former warehouse turned condo complex was completed in 1898
c. 350 W Mart Center: construction on this mixed use commercial space was completed in 1977
If you're keeping score that's three different centuries representin' at that fork in the Chicago River.
Rather impressive, yes?
Is there a tourist activity in your town that you just can't get enough of?
Or have you taken one of the architecture boat tours in Chicago? What'd YOU think?