According to Italian news reports, hundreds of Black Block protesters threw molotov cocktails, torched cars and broke shop windows, while riot police fired tear gas and water cannons.Mired in corruption scandals, the expo has drawn sharp criticism. Critics also accuse authorities of wasting public money and exploiting voluntary labour to run the six-month show. Some 145 countries are represented at the trade fair, that officials hope will attract up to 10 billion euros investment. Credit: Instagram/lukezar">