term is the potential for acid rain. you see, when we get volcanic eruptions like this, sulfur dioxide is erupted into the upper levels of the atmosphere. when we mix that in with rainfall and moisture and oxygen, we have the by-product of acid rain. not saying that has happened. that has been known to happen with previous similar eruptions as well. you mentioned, robyn that the largest lava lake in the world resides within the caldera of this volcano. it's 1.2 kilometers wide in diameter. this is just incredible. you can see the recent eruptions, that 2002 eruption is one that was very fearful for the residents there. that is why they're taking this so seriously. people did perish in that particular eruption, and they left over 200,000 people without homes as they fled the area. mount nyiragongo, a bit of a tongue twister, that erupted at