Two friends have filmed their ascent of a perilous zig-zag hike to the top of a natural fort - in a heavy rain storm. Thrill-seekers Abhishek Kumar Singh and his friend Nishant Neerav took on the notorious Kalavantin Durg, a natural stone fort 2,300ft in the air that is only accessibly by a hand-carved zig-zag staircase. With no handrails or other safety equipment, the climbers faced near-vertical drops either side if they lost their footing in the wet weather. But despite the potential risks, Abhishek said climbing the iconic fort - whose history can be traced back as far as 530BC - was the completion of a life ambition.