By Matias Grez, CNN, Video by Finn McSkimming, CNN, December 17, 2021 (CNN)There are some people out there for who even the word 'daredevil' doesn't quite do justice to the mind-boggling feats they perform. Sebastián Álvarez is one of those people. Last month, the former Chilean Air Force pilot completed what he describes as "by far the most extreme" flight of of his career: flying in and out of the crater of an active volcano. Continues.....