Mauna Kea
Mauna Kea ( or , ) is a dormant volcano on the island of Hawaii. Its peak is above sea level, making it the highest point in the state of Hawaii. Most of the mountain is under water, and when measured from its oceanic base, Mauna Kea is the tallest mountain in the world measuring over . Mauna Kea is about a million years old, and has thus passed the most active shield stage of life hundreds of thousands of years ago. In its current post-shield state, its lava is more viscous, resulting in a steeper profile. Late volcanism has also given it a much rougher appearance than its neighboring volcanoes due to construction of cinder cones, decentralization of its rift zones, glaciation on its peak, and weathering by the prevailing trade winds. Mauna Kea last erupted 6,000 to 4,000 years ago and is now considered dormant. The peak is only about higher than its more massive neighbor, Mauna Loa.
Kīlauea
Kīlauea's high state of activity has a major impact on its mountainside ecology, where plant growth is often interrupted by fresh tephra and drifting volcanic sulfur dioxide, producing acid rains particularly in a barren area south of its southwestern rift zone known as the Kaʻū Desert. Nonetheless, wildlife flourishes where left undisturbed elsewhere on the volcano and is highly endemic thanks to Kīlauea's (and the island of Hawaii's) isolation from the nearest landmass. Historically, the five volcanoes on the island were considered sacred by the Hawaiian people, and in Hawaiian mythology Kīlauea's Halemaumau Crater served as the body and home of Pele, goddess of fire, lightning, wind, and volcanoes. William Ellis, a missionary from England, gave the first modern account of Kīlauea and spent two weeks traveling along the volcano; since its foundation by Thomas Jaggar in 1912, the Hawaiian Volcano Observatory, located on the rim of Kīlauea caldera, has served as the principal investigative and scientific body on the volcano and the island in general. In 1916, a bill forming the Hawaii Volcanoes National Park was signed into law by President Woodrow Wilson; since then, the park has become a World Heritage Site and a major tourist destination, attracting roughly 2.6 million people annually.