Newly elected Greece's opposition leftist party leader Stefanos Kasselakis waves to supporters outside the party's headquarters after winning the leadership elections in Athens on September 25, 2023. A little-known former shipping exec and ex-Goldman Sachs trader on Sunday pulled off one of the biggest upsets in Greek political history after winning the leadership of Syriza, the leftist main opposition party. (Photo by Aris MESSINIS / AFP)