Just as the sun sets, Pavel Demidov and (my assistant) Jeff Wade stop for a rest next to a small lake on their way up to the teams base camp close to the cave entrance high in the Caucasus mountains at 2250m above sea level. In August 2017, 49 years after being discovered, cave explorers reached a depth of -2,212m (7,257ft) in Veryovkina [cave] located in the Caucasus Mountains and set a new record for world’s deepest cave. In September 2018, we joined members of the Perovo Speleo caving team (Moscow) where I wanted to capture the work of the explorers as they pushed the boundaries of exploration deep beneath the earth. It took four days of abseiling (rapelling) and thrutching through tight meandering passages to reach the bottom. We spent a week camped at -2,100m from where we made ‘day’ trips to the bottom.