Two Greenpeace activists scaled CN Tower yesterday (16th July) to hang out a giant protest banner 346 metres above the ground. Steven Guilbeault, 31 from Montreal and Chris Holden, 23, from England apparently climbed the tower rather than abseiled down from the top.The banner read: “Canada and Bush – Climate Killers”. Greenpeace is protesting over the failure of Canada and the United States to ratify the 1997 Kyoto Protocol on climate change. Europe and developing countries support the protocol, which would see a reduction in emissions of greenhouse gases.Defining the Toronto skyline, the CN Tower is Canada´s most recognisable and celebrated icon. At a height of 553.33m (1,815 ft., 5 inches), it was, until recently, the World´s Tallest Building and Free Standing Structure, an important telecommunications hub, and the centre of tourism in Toronto.