is the seventh largest subnational division in the world. If it was an independent nation would be the 17th largest country in the world, larger than Iran. With its myriad islands, Alaska has nearly of tidal shoreline. The Aleutian Islands chain extends west from the southern tip of the Alaska Peninsula. Many active volcanoes are found in the Aleutians and in coastal regions. Unimak Island, for example, is home to Mount Shishaldin, which is an occasionally smoldering volcano that rises to above the North Pacific. The chain of volcanoes extends to Mount Spurr, west of Anchorage on the mainland. Geologists have identified Alaska as part of Wrangellia, a large region consisting of multiple states and Canadian provinces in the Pacific Northwest, which is actively undergoing continent building. One of the world's largest tides occurs in Turnagain Arm, just south of Anchorage, where tidal differences can be more than . Alaska has more than three million lakes. Marshlands and wetland permafrost cover (mostly in northern, western and southwest flatlands). Glacier ice covers about of Alaska. The Bering Glacier is the largest glacier in North America, covering alone. Regions There are no officially defined borders demarcating the various regions of Alaska, but there are six widely accepted regions: South Central The most populous region of Alaska, containing Anchorage, the Matanuska-Susitna Valley and the Kenai Peninsula. Rural, mostly unpopulated areas south of the Alaska Range and west of the Wrangell Mountains also fall within the definition of South Central, as do the Prince William Sound area and the communities of Cordova and Valdez. Southeast Also referred to as the Panhandle or Inside Passage, this is the region of Alaska closest to the contiguous states. As such, this was where most of the initial non-indigenous settlement occurred in the years following the Alaska Purchase. The region is dominated by the Alexander Archipelago as well as the Tongass National Forest, the largest national forest in the United States. It contains the state capital Juneau, the former capital Sitka, and Ketchikan, at one time Alaska's largest city. The Alaska Marine Highway provides a vital surface transportation link throughout the area and country, as only three communities (Haines, Hyder and Skagway) enjoy direct connections to the contiguous North American road system. Interior The Interior is the largest region of Alaska; much of it is uninhabited wilderness. Fairbanks is the only large city in the region. Denali National