Greek transport unions promised chaos for travelers during Thursday's 24-hour general strike, with public transport in Athens forecast to grind to a halt and Olympic Airways and Greek railways scaling back on routes. The 24-hour nationwide strike has been called by Greece's largest labor grouping GSEE, with the support of public sector sister group ADEDY, to protest against plans to reform the country's social security system. The government last week unveiled proposals to revamp the ailing social security system by raising the retirement age, changing how pensions are calculated and doing away with a number of special categories of pensions.