Hawaii from wikipedia

Hawaii's tallest mountain, Mauna Kea stands at 13,796 ft (4,205 m) and is taller than Mount Everest if followed to the base of the mountain—on the floor of the Pacific Ocean.
All of the Hawaiian islands were formed by volcanos erupting from the sea floor from a magma source described in geological theory as a hotspot. The theory maintains that as the tectonic plate beneath much of the Pacific Ocean moves in a northwesterly direction, the hot spot remains stationary, slowly creating new volcanoes. This explains why only volcanoes on the southern half of the Big Island, and the Loihi Seamount (Lōʻihi) deep below the waters off its southern coast, are presently active, with Loihi being the newest volcano to form.
The last volcanic eruption outside the Big Island occurred at Haleakala on Maui in the late 18th century, though recent research suggests that Haleakala's most recent eruptive activity could be hundreds of years earlier.
The volcanic activity and subsequent erosion created impressive geological features. The Big Island is notable as the world’s fifth highest island.