An electrifying look inside the wild world of extreme distance running. Once the reserve of only the most hardcore enthusiasts, ultra running is now a thriving global industry, with hundreds of thousands of competitors each year. B...

Welcome to Japan, the most running-obsessed nation on earth, and home to a unique running culture unlike anything we've ever experienced. It may come as a surprise to many people, but Japan is the most running-obsessed country on eart...