International Space Station in the context of "NASA"

An urban area is a human settlement with a high population density and an infrastructure of built environment. Urban areas originate through urbanization, and researchers categorize them as cities, towns, conurbations or suburbs. In urbanism, the term "urban area" contrasts to rural areas such as villages and hamlets; in urban sociology or urban anthropology, it often contrasts with natural environment.

The development of earlier predecessors of modern urban areas during the urban revolution of the 4th millennium BCEled to the formation of human civilization and ultimately to modern urban planning, which along with other human activities such as exploitation of natural resources has led to a human impact on the environment.

The Bosporus or Bosphorus Strait (/ˈbɒspərəs, ˈbɒsfərəs/ BOSS-pər-əs, BOSS-fər-əs; Turkish: İstanbul Boğazı, lit. 'Istanbul strait', colloquially Boğaz) is a natural strait and an internationally significant waterway located in Turkey which is straddled by the city of Istanbul. The Bosporus connects the Black Sea to the Sea of Marmara and forms one of the continental boundaries between Asia and Europe. It also divides Turkey by separating Asia Minor from Thrace. It is the world's narrowest strait used for international navigation.

Most of the shores of the Bosporus Strait, except for the area to the north, are heavily settled, with the city of Istanbul's metropolitan population of 17 million inhabitants extending inland from both banks.

The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about 85,133,000 km (32,870,000 sq mi). It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for separating the New World of the Americas (North America and South America) from the Old World of Afro-Eurasia (Africa, Asia, and Europe).

Through its separation of Afro-Eurasia from the Americas, the Atlantic Ocean has played a central role in the development of human society, globalization, and the histories of many nations. While the Norse were the first known humans to cross the Atlantic, it was the expedition of Christopher Columbus in 1492 that proved to be the most consequential. Columbus's expedition ushered in an age of exploration and colonization of the Americas by European powers, most notably Portugal, Spain, France, and the United Kingdom. From the 16th to 19th centuries, the Atlantic Ocean was the center of both an eponymous slave trade and the Columbian exchange while occasionally hosting naval battles. Such naval battles, as well as growing trade from regional American powers like the United States and Brazil, both increased in degree during the early 20th century. After World War II, major military operations became rarer, though notable postwar conflicts include the Cuban Missile Crisis and the Falklands War. The ocean remains a core component of trade around the world.

The Milan metropolitan area, also known as Grande Milano ("Greater Milan"), is the largest metropolitan area in Italy and the 54th largest in the world.

The Nile Delta (Arabic: دلتا النيل, Delta an-Nīl or simply الدلتا, ad-Delta) is the delta formed in Lower Egypt where the Nile River spreads out and drains into the Mediterranean Sea. It is one of the world's largest deltas. From Alexandria in the west to Port Said in the east; it covers 240 km (150 mi) of the Mediterranean coastline and is a rich agricultural region. From north to south the delta is approximately 160 km (100 mi) in length. The Delta begins from Cairo.

The Egypt–Israel barrier or Egypt–Israel border fence (Hebrew: שְׁעוֹן הַחוֹל, romanized: Sheʽon HaḤol, lit. 'sand clock') refers to a separation barrier built by Israel along its border with Egypt. Initial construction on the barrier began on 22 November 2010, and its original purpose as a common fence was to curb the large influx of illegal migrants from African countries into Israel. However, in the wake of the Egyptian Crisis after the 2011 Revolution, Israel's southwestern border with Egypt experienced an increase in militant jihadist activity with the outbreak of the Sinai insurgency. In response, Israel upgraded the steel barrier—called Project Hourglass by the Israel Defense Forces (IDF)—to include cameras, radars, and motion detectors. In January 2013, construction on the barrier's main section was completed; the final section was completed in December 2013.

A number of countries, including the United States and India, have sent delegations to Israel to observe its border-controlling capabilities and the various technologies used by the IDF to secure Israel's boundaries against the Arab states. Some of these countries have expressed an interest in implementing Israeli strategies and technologies with their own border fences; the Trump administration cited Israel's border strategies as inspiration for the barrier built by the United States along its border with Mexico, while Indian officials have discussed the implementation of an "Israel-type model" for the barrier built by India along its border with Pakistan.