On the evening of May 22, 2021, Nyiragongo, a mountainous volcano in Democratic Republic of the Congo, suddenly erupted, killing dozens and triggering a pandemonious exodus of swaths of Goma, the city that sits on its flanks. As lava scoured anything it touched, the night sky itself hummed with deep crimson—the heavens themselves looked to be burning down. The eruption appeared to be mercifully short-lived. Molten rock poured from fissures on Nyiragongo’s flanks and sped toward Goma, but ultimately missed the city proper. The lava, which began flowing on Saturday,…