Greece. They also have fans all over the country and in the Greek Diaspora (Germany, Australia, USA, etc.). Research by Marca in August 2018 reported that PAOK are the most popular Greek football team on social media. Toumba Stadium is infamous for its hostile atmosphere, a factor that led to the attribution of the Stadium as "The Black Hell". On high-profile encounters, when the players walk out of the tunnel, the song Hells Bells by AC/DC is heard from the stadium's speakers. The notorious Gate 4 is home to many PAOK organized supporters' groups from around the globe, with the homonymous Gate 4 fan club which was founded in April 1976, being the most familiar everywhere. The supporters' group from Neapoli district of Thessaloniki that was founded in 1963 is the oldest one. One of the biggest banners in the world was created by Michaniona fan club. No 12 jersey is dedicated to the fans, the symbolic 12th man on the pitch. It was permanently retired by the club on 16 August 2000. Vale of Tempe tragedy (4/10/1999) Constantly on tour in order to follow their beloved team everywhere, some 3,000 PAOK fans descended to the Olympic Stadium of Athens for the game against Panathinaikos on 3 October 1999. A few hours later, time stopped. On its way back to Thessaloniki, the double-decker bus of the Kordelio fan club collided with a truck and fell into a ditch in the Vale of Tempe, Thessaly. The aftermath of the bus crash was devastating. Six PAOK fans lost their lives (Kyriakos Lazaridis, Christina Tziova, Anastasios Themelis, Charalampos Zapounidis, Georgios Ganatsios, Dimitris Andreadakis) and many others were injured. A roadside memorial was erected at the site of the crash bearing the following inscription: "Their love for PAOK brought them here, left them here and went beyond". Friendships Partizan CSKA Moscow OFI PAOK fans maintain a strong friendship with the supporters of Serbian club Partizan, the Grobari. On many occasions, fans from both clubs traveled to watch each other's games. Lately, some PAOK supporters' groups have developed a friendship with fans of CSKA Moscow (common Orthodox faith). PAOK fans have good relations with the fans of OFI Crete, a friendship that started in October 1987 when OFI faced Atalanta for 1987–88 Cup Winners' Cup at Toumba Stadium and numerous PAOK fans supported the Cretans. Rivalries Olympiacos Aris Panathinaikos AEK The rivalry between Olympiacos and