Ellsmere Island is 196,235 square kilometres in area and 830 kilometres in length, making it the third largest island in Canada, and the tenth largest in the world. The most mountainous of all the islands in the Canadian Arctic archipelago, it is dominated by the Arctic Cordillera. A national park was proclaimed on Ellsmere Island in 1988, Quttinirpaaq National Park, right on the northern tip, just 800 kilometres from Greenland. The park is covered in the north by the Grant Land Mountains - 100,000 year old rocks shrouded in ice nearly a metre thick, pierced by nunatals (rock spires). This is one of the driest regions in the northern hemisphere, with hardy plants and willow shrubs surviving where there is enough soil for them to be able to send down roots. Here a strange thermal means a surprisingly warm summer in the otherwise, very extreme climate.