In September 2021, after a delay of almost two years caused by COVID-19, I finally made it to the peak of Mount Longonot. This is a 2,780 metre dormant volcano one and a half hour’s drive north of Nairobi, in Kenya. I was hiking with my friends Matthias and Sheila, who I first met in Malawi five years before. It was an overcast day, which kept the temperatures mercifully mild as we followed the steep path up the mountainside. Our first goal was to reach the rim. From here, we could see across the crater, which – unusually for a volcano – was filled with a dense forest, cut off from the outside world by steep cliffs. Its was unclear what wildlife was living down there, although we did see the occasional giraffe on our way up. Great gashes down the mountainsides traced the routes where lava had previously flowed and we found pieces of brittle pumice stone scattered amongst the ash around the crater.