The Mauna Loa volcano is visible in the distance from the slopes of the neighbouring Mauna Kea. It is one of five volcanoes that form the Island of Hawaiʻi, in Hawaii, and makes up more than half of the surface area of the island. Measured from its base on the ocean floor it reaches above 5 miles (8 km) making it the tallest mountain on Earth and considered the largest volcano on Earth. It is so massive that its mass depresses the Earth's crust beneath it by another 5 miles (8 km), meaning the total height of Mauna Loa from the start of its eruptive history is about 10.6 miles (17 km).