Columbus Day weekend holds a special place in the hearts of many Chicago-area runners, as that is the weekend for the city’s huge and esteemed marathon. Nearly 40,000 runners have already beat incredible odds just to arrive at the starting line, and all are anxious about the miles and hours ahead. First-time runners have no real idea what to expect and keep thinking back to all the advice they’ve received. Seasoned runners may have time goals or other personal goals they’re trying to hit. And nobody can ignore the excitement and drama that surrounds such a huge event. You can’t help but reflect on the magnitude of what it takes to bring together tens of thousands of runners and hundreds of thousands of spectators to be a part of a life-altering event in one of the greatest cities on earth.

As I stood way at the back of the pack on Columbus Drive, on the epic date of 10-10-10, I was overwhelmed with how surreal my whole first-marathon experience was. I had only began running 18-months prior, with my ultimate goal being just to run a 5K. Seven months prior, I had scoffed, “Why would anyone ever want to do that to themselves?” But somehow I found myself at the start line of this huge event, surrounded by a sea of people who I knew had been through the same physical and mental challenges as me over the last few months. The sense of camaraderie that came with that realization was huge. I would never talk to most of those people, but we all knew each other, all shared so much in common right then. We were all in one place, with one goal, on that warm October morning as the sun rose over Lake Michigan.

October is a tricky time in Chicago.

You’re just as likely to get scorching heat as frigid cold. In 2009, the starting temperature was 33 degrees. One year later I would be running in a heat index of 95. The heat was definitely the biggest story of the day, and represents one of the biggest truths about running marathons. As much as you prepare, you can’t control the conditions. It might be hot, hilly, humid, dry, cold, windy, rainy, or snowy. But after all the hours and miles you’ve logged to earn that place on the starting line, you’re pretty much willing to fight through anything to see your commitment to the end.

I had joined a large organized training group, courtesy of the charity for which I ran. I was lucky there were about a dozen people at my pace that I knew quite well that I’d be running with. We’d fought through swarms of mosquitos at Waterfall Glen all summer; we were ready to take on the heat of race day. Our pace group had trained at eleven-minute miles, and most of us were first-timers. We knew the dangers of going out too fast, but it was hard not to. You get swept up in the surge of runners, and the roar of spectators makes your forget your plan. I pulled back from my team at around mile six, knowing I had to run my own race. I knew if I kept up the 9:30 pace they had going I would be in big trouble later on.

They say you run the first 10 miles with your muscles, the second 10 miles with your heart, and the last 10K with your spirit. As a very numbers-oriented person, I kept the race broken up in my mind along those same lines. The beginning I just stayed focused on the first ten miles. In the first ten miles you still feel strong, you’re still having fun, and you’re excited to see what lies ahead. The I-can’t-believe-this-is-happening endorphins take you pretty far! The first ten miles of Chicago are especially great, with each neighborhood competing to see who can be the most entertaining.

Then you hit the second ten miles and just focus on that chunk. By this time, for me at least, the fun was well and truly over. It was hot. My time goal had long since evaporated as the mercury continued to rise and the event’s danger-level flags switched from green to yellow to red. I was walking more, ditching articles of clothing, and fighting self-doubt and poor air quality. But somehow you keep going. You tune into your music. You focus on the guy in front of you. You focus just on getting to the next water stop. Or the next minute. The mile markers somehow tick by.

Many say the marathon doesn’t actually begin until mile 20, when you are physically and mentally exhausted. Part of you will say, “But there’s only 10K left. You’ve done that a hundred times!” but the other part whines, “Yes, but that is still another whole HOUR!” The last 6.2 of my first marathon were not pretty. I cried. I stumbled. I walked more than I ran, but somehow kept finding the strength to try again to get back into a rhythm. My A-level goal was gone. My B-level goal shriveled up too. But there was still that C-level goal: finish.

The Chicago Marathon is known for being flat.

Just about the only hills are the overpasses. Unfortunately, there’s a significant hill right at the end. But you know you’re there. There may be 0.2 miles to go, but you know it. You’re there. Your medal, bagel, and patch of grass to collapse on are two minutes ahead. The winners have long since departed with their $100,000 checks, but you’re about to win YOUR race.

And so you surge. You ignore the pain, the fatigue. You put a smile on your face for that finish line camera no matter now miserable you are. Because no matter how bad it got, you did it, you made it, you conquered. Crossing that finish line is about so much more than the last 26.2 miles. It’s about the last six months, or whenever you made that commitment. It’s about going to bed early every Friday night for the past 18 weeks. It’s about slathering on that bug spray even though you know they’re going to eat you alive anyway. It’s about obsessing over weather forecasts. It’s about rearranging your life to fit in your runs.

It’s about fighting through the zombie fugue after your long runs because your family needs you. It’s about finding the time in your schedule for 80-, 90-, and 100-minute runs during the workweek. It’s about looking back on the person you used to be, thinking about how you couldn’t even do the mile in high-school P.E. It’s about your messy house that you’ve been too tired to keep clean. It’s about the look on your kids’ faces when they understand what you’re doing. It’s about dedicating your money to running gear and race fees. It’s about the new habits and superstitions you’ve developed. If you ran for charity, it’s about the cause you dedicated it all to, and about the dozens of donors who believed in you enough to support your cause. It’s about giving up the junk foods because you want to fuel your body with the best there is. It’s about the hundreds of miles pounding the pavement for this quest. It’s about months spent avoiding, managing or fighting injuries. It’s about the t-shirt, the medal, and the bragging rights.

It’s about doing something you will forever be proud of.