Less than one-fourth of the land surface of New Zealand lies below the 200-m (656-ft) contour. The mountain ranges in the North Island do not exceed 1,800 m (6,000 ft) in height, with the exception of the volcanic peaks of Egmont, or Taranaki (2,518 m/8,261 ft), Ruapehu (2,797 m/9,176 ft), Ngauruhoe (2,290 m/7,513 ft), and Tongariro (1,968 m/6,457 ft), the last three of which are still active. This volcanic system gives rise to many hot springs and geysers.
The South Island is significantly more mountainous than the North Island, but is without recent volcanic activity. The Southern Alps, running almost the entire length of the South Island from north to south, contain 19 peaks of 3,000 m (9,800 ft) or above, of which the highest is Mt. Cook or Aorangi, 3,764 m (12,349 ft). There are also several glaciers in the Southern Alps, the largest being the Tasman Glacier, 29 km (18 mi) long and 1 km (0.6 mi) wide. The rivers are mostly swift-flowing and shallow, few of them navigable. There are many lakes, those in the South Island being particularly noted for their magnificent mountain scenery.