There's no smoking gun for this Geo Quiz, but there is a "smoking mountain."
We want you to name a nearly 18,000 ft volcano about 35 miles outside Mexico City.
Its name means "smoking mountain" in the indigenous Nahuatl language.
And it's living up to that name: the volcano's been rumbling and sending up clouds of ash and steam in recent days.
Mexican authorities have raised the alert to level 5 on a 7-point scale.
That's got locals on edge. One resident said "we close our eyes but we don't sleep much".
More than half a million people live in the volcano's shadow and as many as 25 million live within a 60-mile radius.
The mountain we're talking about is the Popocatepetl volcano. Reporter Franc Contreras has been speaking with residents who live in the shadow of 'El Popo'.