Just back: The majesty of Dead Woman's Pass Johan's movements remind me of a bird's, light-footed and rapid. He's burdened by a 70lb backpack that is almost as long as he is tall, and I'm struggling to match his pace. After 80 minutes of trekking we reach a clearing. It's 6am. There is a small shack with a lavatory and, oddly at this painfully cold hour, traditionally dressed Peruvian women selling chocolate bars. They converse with Johan and the other porters in Quechua, the indigenous language. The slabs, laid centuries before by the Incas, are hard work. A foot high and deep, they do not allow you to step onto the next ledge. You have to push yourself onto it, using power rippling from your entire lower body. That this pathway has been created here, laid by man in this remote and challenging terrain, seems implausible, impossible even. We reach sunlight; I overheat and remove layers. My lungs feel as though they are inflating to the size of a tennis ball. Oblivious to the astonishing scenery, all I see are Johan's calves in front of me. Johan is 19. Short, skinny, he is cheerful company, completely devoid of cynicism. It's the fourth time he's trekked to Machu Picchu. His dream is to become a farmer. After 40 more minutes we reach Warmiwañusca, the highest point of our four-day trek, at 13,900ft above sea level. The reward is one of the most stupendous views I'll ever see. Near me, a middle-aged man stands alone before the void, teary-eyed. I climb up onto the dead lady's nipple. Mountain ranges crisscross for miles, their ruffled snow-capped peaks levelled by wisps of chalk-white cloud. Crevices the size of skyscrapers are cast in shadow, and the rest of the rock face seems to have the colour and texture of green velvet. A flow of porters reaches the crest. A few stop to rest and snack, but many continue straight over and start jogging down the pathway to the steps that descend onto a pathway back in time, onto the roadways of an ancient empire. They are machine-like; you would think we had risen 3,300ft this morning on an escalator. With obvious pride, Johan smiles at the travellers, turned monosyllabic by the epic scenery of his country. He gives me a thumbs-up before getting back to work and beginning his descent. Email your entry of no more than 500 words (with the text in the email itself rather than attached) to justback@telegraph.co.uk by midnight on Wednesday, January 25.