Acatenango is a volcano you climb in order to watch a different volcano erupt. The 3,976-metre peak stands in the Guatemalan highlands and looks straight across a narrow saddle at Volcán de Fuego, barely a couple of kilometres away. Fuego is one of the most active volcanoes in the Americas: it has erupted almost without pause since 2002 and throws up a burst of glowing rock every fifteen to twenty minutes. From the camp on Acatenango you are close enough to hear each one and far enough up to stay clear of the ash. Acatenango itself has two summits, the higher Pico Mayor and the older Yepocapa, and it has been quiet since its last eruption in 1972. That silence is the whole reason people can safely spend a night on it. The two cones are joined at the base, and local people call the pair La Horqueta, the pitchfork.
The climb is hard. It is around 1,500 metres of ascent from the village of La Soledad, starting in maize fields and cloud forest and rising through pine and loose volcanic ash. Then the trees give out and you come up above a sea of cloud onto bare open ridge. Most people go overnight and camp near the top, so they are there after dark when Fuego's outline glows orange and each eruption sends lava arcing into the sky and rolling down its flanks. The nights are brutally cold, often around freezing and worse when the wind hits the ridge. In 2017 six hikers who came unprepared died of exposure here, so licensed guides and proper gear are now standard. Before dawn a final push reaches the summit, where Agua and the far volcanoes rise out of the cloud like islands. At nearly 4,000 metres the air is thin, so that last stretch is slow going even for fit walkers.