I said:
800 meters. Pure power isn't enough, nor is sheer, sleek endurance. The elite 800 meter runner must race for all 1:45, with a mind tough yet strategic, full of rage but also completely lucid. The body is subject to pain most of the way, but the runner must steer it hard just the same.
Arguments can be made for any distance, but what the 800 offers is different.
Look at Usain Bolt's races. There is no strategy. He is not genuinely competing. Is he fast? Obviously. But does he care, strategically, what his peers are doing? Only as far as mind games go. For the race, he positions himself in the blocks, waits for the gun, then runs until the race is over. He might see a runner next to him and push harder, but he should push hard anyway. If that other runner inspires him, it only means he wasn't going as tough as he could.
Moreover, so often Bolt slows at the end. He has not demonstrated the kind of focus an 800 meter racer must have.
What about the marathoner? Surely they run a difficult distance. Yes, they do. 26.2 miles is a long way, and, to train properly, the runner must be focused for months on end. However, watch the elites race. By the 10K mark, they are relaxed, in a good rhythm, just cranking out the miles. Granted, these are 4:45 miles, but, for the front runners, a pace they can handle. There is plenty of speed and strategy, but much of the race itself is just getting it done. They run step-in-step for much of the way, and might not "race" until after the 20-mile marker.
Tremendous athletes, to be sure, with incredible desire to run hard and long. They do not, however suffer throughout the distance, not the way an 800 meter runner must suffer.
A similar defense could be made on behalf of the elite 1500 meter runner. He must be fast, with strategy and a strong mind for almost twice the distance. And many race both 800 and 1500 meters. Seb Coe made an incredible career of this, as did Steve Ovett. But strategy matters more in the 1500. An 800 race balances both.
There is no taking away from what the elites endure and accomplish in any distance. The right genes + the the right training + the right mind + the right racing opportunities equals greatness, and whether a 100 meters or 26.2 miles, that's a lot to have.
Me? I was a mediocre 800 runner, with a personal best of 2:07, the slowest by far on a relay team of sub-2:00 runners.
Hmm?
" is likely to help it become a household name. 
is the author of the national bestseller The Perfect Mile, the critically acclaimed Higher, and the award-winning Red Mutiny. A former editor and international journalist, he has also contributed to the New York Times. For Hunting Eichmann, Bascomb tracked down former Nazi soldiers and right-wing radicals in Buenos Aires, traveled to Tel Aviv and Jerusalem to meet with legendary Mossad operatives, uncovered an old memoir by Eichmann on his escape from Germany, and interviewed members of the El Al flight crew involved in Eichmann’s transport to Israel, a story that has never been told. He also made numerous archival discoveries, most notably unearthing the passport that Eichmann used to escape Europe, a discovery that made international headlines.
. Famously, he explained why, though battered, bleeding, and broken, he finished a grueling race in last place, "My country did not send me 5000 miles to start the race. They sent me 5000 miles to finish the race."