The Hawaiian–Emperor seamount chain is a mostly undersea mountain range in the Pacific Ocean that reaches above sea level in Hawaii. It is composed of the Hawaiian ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, and the Emperor Seamounts: together they form a vast underwater mountain region of islands and intervening seamounts, atolls, shallows, banks and reefs along a line trending southeast to northwest beneath the northern Pacific Ocean. The seamount chain, containing over 80 identified undersea volcanoes, stretches about from the Aleutian Trench in the far northwest Pacific to the Kamaʻehuakanaloa Seamount (formerly Lōʻihi), the youngest volcano in the chain, which lies about southeast of the Island of Hawaiʻi. Regions The chain can be divided into three subsections. The first, the Hawaiian archipelago (also known as the Windward isles), consists of the islands comprising the U.S. state of Hawaii. As it is the closest to the hotspot, this volcanically active region is the youngest part of the chain, with ages ranging from 400,000 years to 5.1 million years. The island of Hawaii is composed of five volcanoes, of which four (Kilauea, Mauna Loa, Hualalai, and Mauna Kea) are active. The island of Maui has one active volcano, Haleakalā. Kamaʻehuakanaloa Seamount continues to grow offshore of Hawaii island, and is the only known volcano in the chain in the submarine pre-shield stage. The second part of the chain is composed of the Northwestern Hawaiian Islands, collectively referred to as the Leeward isles, the constituents of which are between 7.2 and 27.7 million years old. Erosion has long since overtaken volcanic activity at these islands, and most of them are atolls, atoll islands, and extinct islands. They contain many of the most northerly atolls in the world; Kure Atoll, in this group, is the northernmost atoll on Earth. On June 15, 2006, U.S. President George W. Bush issued a proclamation creating Papahānaumokuākea Marine National Monument under the Antiquities Act of 1906. The national monument, meant to protect the biodiversity of the Hawaiian isles, encompasses all of the northern isles, and is one of the largest such protected areas in the world. The proclamation limits tourism to the area, and called for a phase-out of fishing by 2011. The oldest and most heavily eroded part of the chain are the Emperor seamounts, which are 39 to 85 million years old. The Emperor and Hawaiian chains form an