A two-day festival, aimed at promoting the decriminalization of cannabis, that was being held at Athens’s Agricultural University this weekend ended with dozens of participants clashing with police and damage to the college. Police said some 3,000 people were taking part in the festival, which began on Friday night, but a group began throwing firebombs at officers and formed barricades around the university at around 3 a.m. on Friday. Police fired tear gas in response but were not able to make any arrests as the assailants hid inside university grounds. Outside the university, Athinon Avenue remained closed until 7.30 a.m. on Saturday until the barricades, which included burning tires, were cleared away. The extent of the damage caused to the university was not immediately clear.