Several large regions are defined as much by culture and history as by physical geography. Scandinavia typically refers to Norway, Sweden, and Denmark, and often includes Finland and Iceland. The Caucasus, a mountainous area between the Black Sea and the Caspian Sea, includes Georgia, Armenia, and Azerbaijan. Mesopotamia, the land between the rivers, lies between the Tigris and Euphrates in modern Iraq and is often called the cradle of civilization. The Indus Valley, in present-day Pakistan and northwest India, gave rise to another of the world's earliest urban civilizations. Patagonia covers the southern tip of South America, shared between Argentina and Chile, while the Outback describes Australia's remote, arid interior.
Grasslands, semi-arid belts, and plateaus give shape to entire continents. The Sahel is a transitional semi-arid region between the Sahara to the north and the wetter savannas to the south, stretching across Africa just south of the desert. The Pampas are fertile lowland plains, mainly in Argentina, while the Eurasian Steppe is a vast belt of grassland stretching from Central Europe to Mongolia. The Tibetan Plateau, often paired with the Pamir Mountains and known as the Roof of the World, is the highest and largest plateau on Earth, averaging well over 4,000 m in elevation. To combat spreading deserts, the Sahel Green Wall is an African-led initiative to grow a continuous belt of trees across the Sahel to fight desertification.
Peninsulas and archipelagos frame some of the world's most distinctive coastlines. The Iberian Peninsula contains Spain, Portugal, Andorra, and Gibraltar, while the Balkan Peninsula in southeastern Europe includes Greece, Bulgaria, Serbia, and several other states. The Malay Archipelago, with Indonesia as its largest country, is the largest archipelago by area. Oceania itself is divided into subregions: Polynesia spans the central and southern Pacific and includes Hawaii, Samoa, and Tonga; Melanesia lies north of Australia and includes Papua New Guinea, the Solomon Islands, Vanuatu, and Fiji; and Micronesia comprises thousands of small islands northeast of Melanesia. Australia is the smallest continent by area. The Red Sea separates Saudi Arabia from Africa, the Persian Gulf lies between Saudi Arabia and Iran, the Aegean Sea sits between Greece and Turkey, and the Mediterranean Sea holds Sicily, its largest island.