Caspian Sea in the context of "Volga Delta"

Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east. Europe shares the landmass of Eurasia with Asia, and of Afro-Eurasia with both Africa and Asia. Europe is commonly considered to be separated from Asia by the watershed of the Ural Mountains, the Ural River, the Caspian Sea, the Greater Caucasus, the Black Sea, and the Turkish straits.

Europe covers approx. 10,186,000 square kilometres (3,933,000 sq mi), or 2% of Earth's surface (6.8% of Earth's land area), making it the second-smallest continent (using the seven-continent model). Politically, Europe is divided into about fifty sovereign states, of which Russia is the largest and most populous, spanning 39% of the continent and comprising 15% of its population. Europe had a total population of about 745 million (about 10% of the world population) in 2021; the third-largest after Asia and Africa. The European climate is affected by warm Atlantic currents, such as the Gulf Stream, which produce a temperate climate, tempering winters and summers, on much of the continent. Further from the sea, seasonal differences are more noticeable producing more continental climates.

The Caucasus (/ˈkɔːkəsəs/) or Caucasia (/kɔːˈkeɪʒə/) is a region spanning Eastern Europe and Western Asia. It is situated between the Black Sea and the Caspian Sea, comprising parts of Southern Russia, Georgia, Armenia, and Azerbaijan. The Caucasus Mountains, including the Greater Caucasus range, have conventionally been considered as a natural barrier between Europe and Asia, bisecting the Eurasian landmass. Mount Elbrus, Europe's highest mountain, is situated in the Western Caucasus area of Russia. On the southern side, the Lesser Caucasus includes the Javakheti Plateau and the Armenian highlands.

The Caucasus is divided into the North Caucasus and South Caucasus, although the Western Caucasus also exists as a distinct geographic space within the North Caucasus. The Greater Caucasus mountain range in the north is mostly shared by Russia and Georgia as well as the northernmost parts of Azerbaijan. The Lesser Caucasus mountain range in the south is mostly located on the territory of southern Georgia, Armenia, and Azerbaijan. The region is known for its linguistic diversity: aside from Indo-European and Turkic languages, the Kartvelian, Northwest Caucasian, and Northeast Caucasian language families are indigenous to the area.

Asia (/ˈeɪʒə/ AY-zhə, UK also /ˈeɪʃə/ AY-shə) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilisations. Its 4.7 billion people constitute roughly 60% of the world's population.

Asia shares the landmass of Eurasia with Europe, and of Afro-Eurasia with both Europe and Africa. In general terms, it is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. A commonly accepted division places Asia to the east of the Suez Canal separating it from Africa; and to the east of the Turkish straits, the Ural Mountains and Ural River, and to the south of the Caucasus Mountains and the Caspian and Black seas, separating it from Europe.

West Asia (also called Western Asia or Southwest Asia) is the westernmost region of Asia. As defined by most academics, UN bodies and other institutions, the subregion consists of Anatolia, the Arabian Peninsula, Iran, Mesopotamia, the Armenian highlands, the Levant, the island of Cyprus, the Sinai Peninsula and the South Caucasus. The region is separated from Africa by the Isthmus of Suez in Egypt, and separated from Europe by the waterways of the Turkish Straits and the watershed of the Greater Caucasus. Central Asia lies to its northeast, while South Asia lies to its east. Twelve seas surround the region (clockwise): the Aegean Sea, the Sea of Marmara, the Black Sea, the Caspian Sea, the Persian Gulf, the Gulf of Oman, the Arabian Sea, the Gulf of Aden, the Red Sea, the Gulf of Aqaba, the Gulf of Suez, and the Mediterranean Sea. West Asia contains the majority of the similarly defined Middle East. The Middle East is a political term invented by Western geographers that has historically included various territories depending on political and historical context, while West Asia is a geographical term with more accuracy and consistency. It excludes most of Egypt and the northwestern part of Turkey, and includes the southern part of the Caucasus.

West Asia covers an area of 5,994,935 km (2,314,657 sq mi), with a population of about 313 million. Of the 20 UN member countries fully or partly within the region, 13 are part of the Arab world. The most populous countries in West Asia are Iran, Turkey, Iraq, Saudi Arabia and Yemen.

Azerbaijan, officially the Republic of Azerbaijan, is a transcontinental and landlocked country at the boundary of Western Asia and Eastern Europe. It is a part of the South Caucasus region and is bounded by the Caspian Sea to the east, Russia's republic of Dagestan to the north, Georgia to the northwest, Armenia and Turkey to the west, and Iran to the south. Baku is the capital and largest city.

The territory of what is now Azerbaijan was ruled first by Caucasian Albania and later by various Persian empires. Until the 19th century, it remained part of Qajar Iran, but the Russo-Persian wars of 1804–1813 and 1826–1828 forced the Qajar Empire to cede its Caucasian territories to the Russian Empire; the treaties of Gulistan in 1813 and Turkmenchay in 1828 defined the border between Russia and Iran. The region north of the Aras was part of Iran until it was conquered by Russia in the 19th century, where it was administered as part of the Caucasus Viceroyalty.

Iran, officially the Islamic Republic of Iran and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the northeast, Afghanistan to the east, Pakistan to the southeast, and the Gulf of Oman and the Persian Gulf to the south. With a population of over 90 million, Iran ranks 17th globally in both geographic size and population and is the sixth-largest country in Asia. Iran is divided into five regions with 31 provinces. Tehran is the nation's capital, largest city, and financial center.

Home to one of the world's oldest continuous major civilizations, most of Iran was first united as a nation by the Medes under Cyaxares in the 7th century BC and reached its territorial height in the 6th century BC, when Cyrus the Great founded the Achaemenid Empire. Alexander the Great conquered the empire in the 4th century BC. An Iranian rebellion in the 3rd century BC established the Parthian Empire, which later liberated the country. In the 3rd century CE, the Parthians were succeeded by the Sasanian Empire, who oversaw a golden age in the history of Iranian civilization. During this period, ancient Iran saw some of the earliest developments of writing, agriculture, urbanization, religion, and administration. Once a center for Zoroastrianism, the 7th century CE Muslim conquest brought about the Islamization of Iran. Innovations in literature, philosophy, mathematics, medicine, astronomy and art were renewed during the Islamic Golden Age and Iranian Intermezzo, a period during which Iranian Muslim dynasties ended Arab rule and revived the Persian language. This era was followed by Seljuk and Khwarazmian rule, Mongol conquests and the Timurid Renaissance from the 11th to 14th centuries.

The Messinian salinity crisis (also referred to as the Messinian event, and in its latest stage as the Lago Mare event) was an event in which the Mediterranean Sea went into a cycle of partial or nearly complete desiccation (drying-up) throughout the latter part of the Messinian age of the Miocene epoch, from 5.96 to 5.33 Ma (million years ago). It ended with the Zanclean flood, when the Atlantic reclaimed the basin.

Sediment samples from below the deep seafloor of the Mediterranean Sea, which include evaporite minerals, soils, and fossil plants, show that the precursor of the Strait of Gibraltar closed about 5.96 million years ago, sealing the Mediterranean off from the Atlantic. This resulted in a period of partial desiccation of the Mediterranean Sea, the first of several such periods during the late Miocene. After the strait closed for the last time around 5.6 Ma, the region's generally dry climate at the time dried the Mediterranean basin out nearly completely within a thousand years. This massive desiccation left a deep dry basin, reaching 3 to 5 km (1.9 to 3.1 mi) deep below normal sea level, with a few hypersaline pockets similar to today's Dead Sea. Then, around 5.5 Ma, wetter climatic conditions resulted in the basin receiving more fresh water from rivers, progressively filling and diluting the hypersaline lakes into larger pockets of brackish water (much like today's Caspian Sea). The Messinian salinity crisis ended with the Strait of Gibraltar finally reopening 5.33 Ma, when the Atlantic rapidly filled up the Mediterranean basin in what is known as the Zanclean flood.

Batumi (/bɑːˈtuːmi/; Georgian: ბათუმი pronounced [ˈb̥a'tʰu.mi] ), historically Batum or Batoum, is the second-largest city of Georgia and the capital of the Autonomous Republic of Adjara. Located on the eastern shore of the Black Sea, about 20 kilometres (12 mi) north of the Georgia–Turkey border, Batumi lies at the foot of the Caucasus Mountains in a humid subtropical zone. As one of the country’s principal urban centers, it serves as a major seaport, commercial hub, and cultural gateway between Europe and Asia.

The city has played a significant role in the history of the south-eastern Black Sea region due to its deep-water harbor and strategic position along regional trade routes. Over the centuries, Batumi has been ruled by the Kingdom of Georgia, the Ottoman Empire, the Russian Empire, and the Soviet Union, each leaving distinct cultural and architectural imprints. Its economy historically relied on maritime trade and oil transit, particularly following the construction of the Baku–Batumi pipeline in the early 20th century. Today, it remains a key transit point for Caspian energy exports and regional commerce.

The Sea of Azov is an inland shelf sea in Eastern Europe connected to the Black Sea by the narrow (about 4 km (2.5 mi)) Strait of Kerch, and sometimes regarded as a northern extension of the Black Sea. The sea is bounded by Russia on the east, and by Ukraine on the northwest and southwest (the parts of Ukraine bordering the sea are currently under Russian occupation). It is an important access route for Central Asia, from the Caspian Sea via the Volga–Don Canal.

The sea is largely affected by the inflow of the Don, Kuban, and other rivers, which bring sand, silt, and shells, which in turn form numerous bays, limans, and narrow spits. Because of these deposits, the sea bottom is relatively smooth and flat, with the depth gradually increasing toward the middle. Because of the river inflow, water in the sea has low salinity and a high amount of biomass (such as green algae) that affects the water colour. Abundant plankton result in unusually high fish productivity. The sea shores and spits are low; they are rich in vegetation and bird colonies. The Sea of Azov is the shallowest sea in the world, with the depth varying between 0.9 and 14 metres (3 and 46 ft). There is a constant outflow of water from the Sea of Azov to the Black Sea.

The Caucasus Mountains is a mountain range at the intersection of Asia and Europe. Stretching between the Black Sea and the Caspian Sea, they are surrounded by the Caucasus region and are home to Mount Elbrus, the highest peak in Europe at 5,642 metres (18,510 ft) above sea level.

The Caucasus Mountains include the Greater Caucasus in the north and the Lesser Caucasus in the south. The Greater Caucasus runs west-northwest to east-southeast, from the Western Caucasus on the northeastern shore of the Black Sea to close to Baku on the Caspian Sea, in Azerbaijan. The Lesser Caucasus runs parallel to the Greater about 100 km (62 mi) south. The Greater and Lesser Caucasus ranges are connected by the Likhi Range, and to the west and east of the Likhi Range lie the Colchis Plain and the Kur-Araz Lowland respectively. The Meskheti Range is a part of the Lesser Caucasus system. In the southeast, the Aras River separates the Lesser Caucasus from the Talysh Mountains which runs through the Greater Azerbaijan region. The Lesser Caucasus and the Armenian Highland constitute the Transcaucasian Highland, which at their western end converges with the highland plateau of Eastern Anatolia. The Caucasus Mountains were part of the Silk Road.