I have often traveled to Chicago — for clients in my litigator days, and for meetings and bar work including with the ABA and several other organizations in my years of service as a federal judge. But I have never experienced Chicago like I did on Oct. 9, a glorious Sunday, when I ran my first Chicago Marathon wearing a white T-shirt proclaiming, “The Constitution Works!”

Forty thousand runners may well have 40,000 different reasons to dream of running the Chicago Marathon. For some, it comes down to a “bucket list” — but after my experience last month, and having run four other marathons in New York and Boston, I’m convinced that the Chicago Marathon should not be something you just want to check off a list. Here’s why.

Chicago’s spectators may be the best sports fans anywhere. They are loud, bold, funny and relentless. They never give up on you -— they didn’t give up on the Cubs, did they? They’re not just rooting for the world-class runners at the front of the pack, or the people they know, but for everyone.

Chicago’s neighborhoods are amazing. The people, sights, sounds, even smells. The experts tell you that you will run through no less than 29 neighborhoods, from the business areas of downtown to the residential and outdoor areas of the North Side to the thrill of Wrigleyville. Once you double back south, across the Chicago River and onward, one of my favorite neighborhood experiences comes in Greektown, with its signs, restaurants and bakeries, then Little Italy, Pilsen with handouts of fruit slices and juices, and music and costumes in Chinatown. And for the last few miles, Armour Square, Bronzeville, The Gap, Prairie Shores, Motor Row District, the South Loop.

And finally, Grant Park — where you began. Is that a neighborhood too? It is on Marathon Sunday.

Chicago’s music will keep you stepping. The official live bands and maybe even more the unofficial, ad hoc music stations, marching bands, drums, and everything else, will engage you, make you smile, and maybe most important in those last 10 miles, help to lift your feet up off the pavement, step after step after step. You can’t dance, not quite yet, but you can run!

Back to the fans. They are funny! Quirky! Joyful! Their signs and cheers are fantastic! And even when they aren’t for you, they are for you. “Go, Mom!?” I’m mom!

Some signs are political, and very funny. Some are a bit off color (yes, there are biological aspects to running 26.2 miles, not all of them pleasant), and these are very funny too. How about “Toenails are overrated” or the perennial marathon classic, “Remember, you paid to do this!” Oh and my personal favorite, perhaps because I identify with it so strongly, “Go, random stranger!” I’m a “random stranger!”

So many good causes. There are the official good causes, and these are the more than 170 different charity partners of the event. These include some that are special to me, like the suicide prevention center. My mom was a suicide prevention counselor for 25 years. But then there are the unofficial good causes. These can be very personal. For me, I dedicate every marathon and half marathon to my sister Connie, a three-time cancer survivor.

So many people had bibs or shirts declaring “I run for my dad,” or my mom, or my friend, or my child. Or sometimes, “I run to honor their memory.” Ask anyone who has completed an event like this — even if it isn’t on your bib or their back, these thoughts are in your mind and in your heart.

The finish line! Maybe everything hurts, maybe you can barely stand up, but still, you can’t stop grinning. A volunteer hands you water, another drapes a gorgeous medal on a gorgeous wide red ribbon around your neck. You did it! You ran Chicago! (For me, that was in 21,580th place with a time of 4:29:53.) Maybe you’ll never have to do this again — or maybe, just maybe, you’ll apply again next year.

And that’s the point. The reason you should not put the Chicago Marathon on your bucket list is all of these reasons — because no one should run Chicago just once.

Registration is open until 2 p.m. Nov. 17 for the 45th Bank of America Chicago Marathon, which will be run Oct. 8, 2023.