Athens Challenge 2015 Playlist https://www.youtube.com/playlist?list=PLfOZPjBsthyOXT-O3UvvxlVG5MWq700tz

Athens Challenge 2014 Playlist https://www.youtube.com/watch?v=bifeg19I5lI&list=PLfOZPjBsthyO-CMiHYzo62cQctoZUH2LU

Athens challenge 2012 playlist https://www.youtube.com/watch?v=czgnkEpqevk&list=PL3B1F9B3472403399

Athens Challenge 2011 Playlist https://www.youtube.com/watch?v=axmP_9HTSxQ&list=PLfOZPjBsthyM87DJz8CeTqswx7Ic6TcSx