Tension broke in downtown Athens, Greece, near the Polytechnic School around 5 pm on Saturday, May 23. The episodes started after the end of an anti-authoritarian rally that took place in the area, at the German Embassy. A group of anti-authoritarians stopped a moving trolleybus, they demanded from the passengers to get off the vehicle and then set it on fire. Firemen arrived on the scene immediately and managed to put out the fire before any major damage was caused in the area. However, the vehicle was completely destroyed. Later, the group, consisting of 50 people, moved toward the Polytechnic school, where they clashed with Greek police, throwing rocks, while the officers responded with stun grenades.