Flights to and from Greece were halted today, Thursday, following a strike by union workers in protest of a train collision that claimed the lives of 57 people on February 28. Consequently, private and public sector unions called for a strike, the latest in a series of protests since the accident, which involved a train carrying 350 passengers, mostly university students. Public services were suspended, and government schools closed for 24 hours today, with urban transport disrupted as taxi drivers and subway workers joined the strike. Railway workers have been engaged in ongoing strikes since the collision occurred.