In January 2002, a volcano dumped a million cubic meters of molten lava straight into an African lake secretly hoarding enough gas to wipe out a city. You'd expect an apocalyptic explosion. Instead, nothing happened.

This episode dives into Lake Kivu on the Rwanda–DRC border, a body of water that breaks the rules of geology and biology. We explore why this 480-meter-deep lake is a ticking time bomb, how engineers are turning that existential threat into electricity, and how humans have rewired the lake from top to bottom.

• How tectonic damming and a meromictic structure created a vault of roughly 65 cubic kilometers of methane and 256 cubic kilometers of CO2 in the deep water.
• The horror of a "limnic eruption" — the same phenomenon that struck Lakes Nyos and Monoun in Cameroon — and sediment evidence of mass die-offs rough ...