North America metropolitan area by population in North America: Greater Mexico City. Canada also breaks into the top ten largest metropolitan areas with the Toronto metropolitan area having six million people. The proximity of cities to each other on the Canada–United States border and Mexico–United States border has led to the rise of international metropolitan areas. These urban agglomerations are observed at their largest and most productive in Detroit–Windsor and San Diego–Tijuana and experience large commercial, economic, and cultural activity. The metropolitan areas are responsible for millions of dollars of trade dependent on international freight. In Detroit-Windsor the Border Transportation Partnership study
North America The islands of the West Indies delineate a submerged former land bridge, which had connected North and South America via what are now Florida and Venezuela. There are numerous islands off the continent's coasts; principally, the Arctic Archipelago, the Bahamas, Turks & Caicos, the Greater and Lesser Antilles, the Aleutian Islands (some of which are in the Eastern Hemisphere proper), the Alexander Archipelago, the many thousand islands of the British Columbia Coast, and Newfoundland. Greenland, a self-governing Danish island, and the world's largest, is on the same tectonic plate (the North American Plate) and is part of North America geographically.