Berlin is 19 days away. What actually happens on 27 September

On Sunday 27 September, roughly 55,000 people will run through Berlin. It is the largest marathon on earth by finishers, and it is not close.

It is also the fastest. Every men’s world record but one since 2003 has been set on these streets, and the reason is unglamorous: Berlin is flat, wide, sheltered by buildings for most of its length, and run in late-September air that is usually about eight degrees at the start. There is no hill to ruin your pacing and no exposed section to wreck it.

If you are running

The taper is not a rest week, it is a sharpening week. Keep the frequency, cut the volume, keep some pace in the legs. The universal Berlin mistake is arriving fresh but flat because the last hard session was eleven days ago.

Two practical things. The start pens on Straße des 17. Juni are enormous and slow to move — budget far more time than seems reasonable. And the Tiergarten at 8am in late September is genuinely cold; whatever you plan to throw away at the gun, bring more of it.

If you are watching

The course loops enough that a spectator on foot can comfortably see runners three times. The classic is somewhere in the first 10km, then Potsdamer Platz around 38km — the point where the race stops being about fitness — and then the Brandenburg Gate.

That last 400 metres, from the Gate to the line on Straße des 17. Juni, is the best-known stretch of road in distance running. It is worth standing there even if you know nobody in the race.

If you are neither

Berlin is the unofficial start of the European autumn. Cologne follows a week later, Munich and Eindhoven the week after that, then Amsterdam, then Frankfurt and Dublin on the same Sunday in October.

Then it gets dark, and the season changes shape entirely.