Part of the Golden Trail World Series , Sierre-Zinal is raced along a daunting 31km trail with a 2 200m elevation gain and a 1 100m vertical drop in the Swiss Canton of Valais .
PHOTOGRAPHS MARTINA VALMASSOI ( LEFT ), ACEA RUN ROME ( BOTTOM LEFT ), UTMB WORLD SERIES ( RIGHT )
The famous Maratona Di Roma starts on the Via dei Fori Imperiali in the shadow of the Colosseum , before taking runners on a tour of the Eternal City .
18 | RUN FOR YOUR LIFE