Some information to share about the 4 spectacular marathons on three different continents.
Focusing on extreme elements such as high altitude, steep ascents, sand dunes, cold/frost or heat.

The Great Wall Marathon on the Great Wall in China
The Big Five Marathon on the savannah in South Africa
The Great Tibetan Marathon in the mountains of Tibet
The Polar Circle Marathon on the ice cap in Greenland

Details are available in the website

http://www.adventure-marathon.com/