The Hawaiian-Emperor Seamount is a prominent line of underwater mountains in the north-central Pacific Ocean that stretches 4,300 miles (6,919 kilometers) from the Aleutian Islands south to the Hawaiian Islands. Cutting through three Pacific basins (Northwest, Northeast, and Central), the seamount, also known as a ridge, is built from at least 125 large volcanoes and hundreds of smaller peaks. The mountains are up to 30 miles (48 kilometers) wide, and many soar 20,000 feet (6,096 meters) from the ocean bottom. Key islands in this undersea chain include the Hawaiian Islands, the Midway Atoll, and several smaller uninhabited reefs.