I spent my teenager years living in Pasadena, Texas, a suburb of Houston. We moved there from Little Rock when I was eleven, and the first "fact" I remember was that the highest point in Houston was an overpass. This may have been a joke (my stepfather was full of these kinds of things) but judging from these overpasses, not too much of one. There are several places in Houston that my mom called "spaghetti bowls" where several directions and lanes from several intersecting freeways merge and connect. These are from Google Maps.
As a kid, these fascinated me. As a teenager and young adult trying to drive on them (as well as the ones in Dallas), they infuriated me, and now as an adult who drives mainly in Philadelphia and New Jersey, where they have other kids of bizarre transportation issues, they fascinate me again.
You can see a pretty strong inspiration from these highway intersections in my puzzle that was published by Mudpuppy a few weeks ago, and now I'm working on a big book about cars and trucks and other forms of transportation (yes yes, again, mais pas en Francais!) and I've been collecting photographs for reference. I spent a chunk of time this morning looking on Flickr for good overpass/highway pictures and I just want to share. So many amazing things.
And one of my own taken from a bus in New York City: