Megadeth live in Beunos Ares. Dream Theater played here as well and it was insane. The Argentine people have an energy about them that is unrivaled in the world. They sing the guitar parts like chants. It is intoxicating.
I couldn't get the whole thing on youtube, but I would encourage you to find it. Megadeth is the greatest band of all time, and I'll fight anybody who says otherwise :)