Gurgaon's roads host several runs, marathons, and cycling rides every weekend. But this time, it was the turn of the forests on the foothills of the Aravallis on the outskirts of the Millennium City. This Sunday, at the fifth edition of Gurgaon's annual Trail-a-thon that saw nearly 2000 runners, walkers, and cyclists make their way through the Aravalli trails starting from Mangar Village on the Gurgaon-Faridabad Road to Damdama Lake in the interiors of the woods.