premise: A series of firebomb attacks targeting banks in Athens occurred Wednesday overnight, days before the 33rd anniversary of the Polytechnic students' uprising in 1973.
  The first firebomb attack, which targeted a National Bank branch in the Peristeri district, damaged an ATM and the bank's entrance. A few minutes later, the entrance of another National Bank branch in Paleo Faliro was also wrecked by fire.
  In Holargos district, a firebomb caused minor damage to a third National Bank branch.
  Extensive damages were also reported following a firebomb raid against an Emporiki Bank branch in downtown Athens.
   What is the cause of the upcoming anniversary?
hypothesis: Polytechnic students' uprising in 1973