But the world's tallest mountain from base (below sea level) to peak is Mauna Kea (in Hawaii). It's 33,476 feet tall, but only its top 13,803 feet extend above sea level. Its base is on the sea floor and it rises 33,480 feet (10,314 meters) in total, reaching 13,796 feet (4205 m) above sea level.

more facts about tallest mountains

Mount Everest (all all the other mountains in Himalayas) are still growing higher, at a rate of about 2.4 in/6.1cm per year, as the Indian Tectonic Plate slides north under the Eurasian Plate.

Here is the list of other tall mountains in the world: Mountain Peak Range

Everest Himalayas Nepal, Asia 29,035 (ft) 8,850 (m)

K2 (Godwin Austen)Karakoram Pakistan, Asia 28,253 (ft) 8,612(m)

Kanchenjunga Himalayas Nepal, Asia 28,169 (ft) 8,586 (m)

Lhotse I Himalayas Nepal, Asia 27,920 (ft) 8,501 (m)

Makalu I Himalayas Nepal, Asia 27,765 (ft) 8,462 (m)

Cho Oyu Himalayas Nepal, Asia 26,906 (ft) 8,201 (m)

Dhaulagiri Himalayas Nepal, Asia 26,794 (ft) 8,167 (m)

Manaslu Himalayas Nepal, Asia 26,758 (ft) 8,156 (m)