## TL;DR

The marathon (42.195 km / 26.2 miles) is the ultimate test of endurance. Origin: Pheidippides ran from Marathon to Athens to announce Greek victory (490 BCE) — then died. Modern marathon: first Olympic event (1896). World record: Kelvin Kiptum (2:00:35, Chicago 2023). Sub-2 hour barrier: Eliud Kipchoge (1:59:40, Vienna 2019, unofficial).

## Core Explanation

Training: 16-20 week plan, peak weekly mileage 50-100km. Long run: cornerstone, weekly, building to 32-35km. Nutrition: carb-loading (3 days before), gels during race (every 30-45 min). Wall (bonking): glycogen depletion at ~30-35km — avoid by pacing and fueling. Boston Marathon (1897, oldest annual). Big 6: Boston, London, Berlin, Chicago, NYC, Tokyo. 'The marathon doesn't start until mile 20.'

## Further Reading

- [Advanced Marathoning (Pfitzinger & Douglas, 3rd Ed)](https://www.humankinetics.com/products/advanced-marathoning-3rd-edition)