Going for a dip in the Seine on a hot summer's day has been the pipedream of many Parisians since swimming in the river was formally banned a century ago. But floating on your back under the Eiffel Tower could very soon become reality thanks to the Paris Olympics. The river will be the star of the opening ceremony of the Games on 26 July and will host the triathlon and the swimming marathon. Then, if all goes well, next summer Parisians and tourists will be able to swim in it too. Some 1.4 billion euros has been spent on colossal public works to counter pollution.