The Nuremberg Toy Fair, the world's biggest toy expo, opened Thursday in Germany with one of its focuses on packaging boys' toys to make them more attractive to girls, according to dpa. Within an hour of the opening, the city's exhibition centre was already packed with people. Organizers expect 76,000 trade visitors, mainly purchasing executives and merchants, to visit by the closing day Tuesday. Nearly 2,700 exhibiting companies from around the world have about 1 million products available in their catalogues. Manufacturers say 70,000 are new, though that includes long-standing toys that are being offered in additional colours or from new plastic moulds. On Wednesday, toy professionals attended a "building our future" conference in Nuremberg on why toys tend to be firmly aimed at either boys or girls. Richard Gottlieb, who chaired the discussion, said Thursday in an interview, the photographs on the packaging often spread the message that a boy will usually end up in charge of a science toy or a ride- on toy. Where girls are shown in the images, they are usually only helpers or onlookers, the US-based consultant said. Gottlieb said he had been urging manufacturers to change the packaging. The fair also focuses on rising consumer demand for toy manufacturers to be environmentally sensitive. German ecology groups claimed the previous day that plastic used for toys contained too much of certain toxic substances. A wristwatch for "secret agents" aged between six and 10 has been named "toy of the fair". The Spynet Video Watch from US company Jakks Pacific contains a video camera and a lie detector. It also tells the time. The fair has introduced a Green Toys award this year. It went to a model moonbase with action figures, the E-Rangers Future Base from the German brand Playmobil. It includes a functioning solar panel and educates children about scarce natural resources.