The region includes a series of mountain ranges, notably the Tararua Range and the Ruahine Range and the three major active volcanoes of the North Island. Mount Ruapehu at 2,797 m is the tallest mountain in the North Island, Ngauruhoe 2,291 m and Tongariro 1,968 m. During the last 100 years Ruapehu has experienced six significant eruptions, and last erupted in 1995 and 1996.