The H.C. Andersen Marathon (HCA Marathon) is a marathon in Odense, Denmark, which was established in 2000. From 2006 onwards, the event has included a half marathon and from 2017 a 10K race "Run the last 10".
HCA Marathon is named after the Danish fairy-tale writer Hans Christian Andersen.
HCA Marathon is the world's fastest marathon in 2019. On average the runners finish the marathon in just 3:51:22 which is just 8 minutes 50 second a mile. HCA Marathon is also the marathon with the cleanest air in the world. https://thesolesupplier.co.uk/news/up-for-a-challenge-these-are-the-worlds-best-marathon-courses/
The race is held on a round course, starting and finishing at Odense Idrætspark. The course is run twice, and the finish is in the athletics stadium.