49 Fun Facts About Caspian Sea

The Caspian Sea holds what distinction among the world's lakes and seas?

Largest inland one. It has a seagoing past: its basin was joined to the world ocean until it was cut off millions of years ago, and the stranded water is still salty.

The 1971 treaty named after Ramsar, an Iranian resort on the Caspian, protects what?

Wetlands. Delegates signed it in the resort in February 1971, and the marshes and lakes it protects around the world are now known as Ramsar sites.

In Iran today the Caspian is often called by what name, after a province on its southern shore?

The Mazandaran Sea. Over the centuries Persian writers named the sea after whichever people, town or province on its shores mattered most, and this lush northern province is the name in use now.

The Caspian Sea covers roughly the same area as which country?

Japan. A lake on that scale dwarfs the famous ones: it is about one and a half times the area of all five North American Great Lakes put together.

The surface of the Caspian Sea lies roughly how far below global sea level?

About 27 metres. The level never sits still: it fell by roughly three metres between 1929 and 1977, then climbed back almost as far over the next two decades.

How salty is the Caspian compared with the open ocean?

A third as salty. Rivers freshen it so much near their mouths that the water there is nearly fresh, while one shallow gulf evaporates into brine far saltier than any ocean.

Azerbaijan's Caspian shore has the world's greatest concentration of which natural feature?

Mud volcanoes. Underground gas pushes cool mud up into cones that can stand hundreds of metres high, and when a big one erupts the gas can catch fire and send up a flame just as tall.

In October 2015 Russian warships on the Caspian fired cruise missiles some 1,500 km at targets in which country?

Syria. Four small ships launched 26 missiles that crossed Iran and Iraq on the way, showing how far beyond its own shores the little Caspian flotilla could reach.

The Caspian is a stranded remnant of which vanished ocean, named after a sea goddess of Greek myth?

The Tethys. As that ocean closed, an arm of it was cut off across Eurasia and slowly shrank, leaving the Caspian and its neighbours behind as remnants.

Which river flows through Tbilisi and on across Azerbaijan to reach the Caspian?

The Kura. Georgians call it the Mtkvari, and it no longer runs free: one dam stands just above Tbilisi, and another in Azerbaijan holds back a great reservoir.

Which mountain range, crowned by Mount Damavand, walls off the Caspian's southern shore from the Iranian plateau?

The Alborz. Its seaward face wrings the moisture out of the Caspian air, so that slope is drenched and green while the far side, just over the passes, is dry.

Which Central Asian river is thought to have once sent water to the Caspian along the now-dry Uzboy channel?

The Amu Darya (Oxus). The dry Uzboy bed still winds across the Karakum desert toward the Caspian, though geologists argue to this day over how much of the great river ever ran down it.

Dammed off from the Caspian in 1980, the Garabogazköl lagoon did what within four years?

Dried out. Planners feared the lagoon was draining the Caspian, but cutting it off left a bowl of blowing salt, and the barrier was torn out in 1992 once the sea had risen again.

From 1973 to 1999 the desert port of Aktau made its drinking water from the Caspian using what?

A nuclear reactor. The Soviet BN-350 fast reactor lit the city and distilled seawater for it; Aktau later hosted the 2018 summit where the five coastal states signed the Caspian's legal convention.

Legally, after the 2018 convention, the Caspian Sea is defined as what?

Neither fully a sea nor a lake. The surface is shared like open sea while the seabed, with its oil and gas, is left for the five states to divide by agreement, easing a dispute that began when the Soviet Union broke up.

Astrakhan, the Russian port near the Caspian, gave its name to a fur made from newborn what?

Lambs. The tight curls come from newborn Karakul lambs of Central Asia, and the name passed on to a woollen cloth woven to imitate them.

Which Swedish family built the oil company that dominated Baku's Caspian boom from the 1870s?

The Nobels. Robert set up in Baku in 1873 and drew in his brother Ludvig; their firm became one of the largest oil companies in the world, with a third brother, Alfred of dynamite fame, as a shareholder.

Which James Bond film sends 007 to Azerbaijan to protect an heiress building an oil pipeline from the Caspian?

The World Is Not Enough. The 1999 film moves from the pipeline's mountain route to a caviar dealer's factory out in the Caspian, where the heiress Bond was sent to guard has him attacked by her helicopters.

Baku is the largest city on the Caspian and also the largest in which mountainous region?

The Caucasus. Oil made the city: around 1900 the fields at Baku were the most productive on Earth and pumped about half of the world's supply.

Baku is widely nicknamed the 'City of' what?

Winds. A cold gale that can gust to nearly 150 km/h and a warm counterpart, the gilavar, take turns over the city, and one or the other is blowing in every season.

Baku's UNESCO-listed Old City contains the Palace of the Shirvanshahs and which famous landmark?

The Maiden Tower. The stone tower, usually dated to the 12th century, is still the city's emblem, though the skyline behind it now belongs to three glass skyscrapers shaped like flames.

Yanar Dag, a hillside near Baku, has been famous for decades for doing what without a pause?

Burning. Natural gas seeping up through the rock feeds flames as much as three metres high, day and night; hillside fires like it earned Azerbaijan the name Land of Fire.

Which annual televised event did Baku host in 2012?

Eurovision. Azerbaijan earned the right to host by winning in 2011 at only its fourth attempt, and put up the Baku Crystal Hall for the show in about eight months.

The first successful oil tanker, built for the Caspian trade, was named after which prophet?

Zoroaster. While other shippers still moved oil in wooden casks, the steamer carried it in bulk in built-in tanks, and it reached the Caspian from its Swedish shipyard by way of Russia's rivers and canals.

The Caspian's beluga sturgeon shares its name with the beluga whale; what does the Russian word behind 'beluga' mean?

White. The name belonged to the pale sturgeon first, the fish behind beluga caviar, and was only later passed on to the unrelated white whale of the Arctic.

What is the IUCN conservation status of the beluga sturgeon, hunted for its caviar?

Critically endangered. So many egg-bearing females have been caught for caviar, legally and by poachers, that the 2019 assessment found the wild fish surviving largely thanks to hatchery restocking.

Traditionally, 'caviar' means only wild sturgeon roe from the Caspian and which other sea?

The Black Sea. By that old rule the red roe of salmon is not caviar at all, and the cheap jars of lumpfish roe are dyed black with cuttlefish ink to pass for the real thing.

What is the only aquatic mammal endemic to the Caspian Sea?

A seal. Its closest relatives are the ringed seal of the Arctic and the seal of Lake Baikal, and its ancestors probably reached the Caspian along rivers that have long since vanished.

Which tiger, the extinct Caspian tiger's closest relative, was sent to Kazakhstan in 2024?

Siberian. Genetic work suggests the two were one continuous population until people split their range in recent centuries, so a captive pair was moved to a reserve near Lake Balkhash in the hope that their cubs can live wild.

The experimental Soviet craft nicknamed the 'Caspian Sea Monster' was what kind of vehicle?

A ground-effect ekranoplan. Skimming just above the water let it fly fast while staying too low for many radars to spot, a mix the Soviet navy tested for years.

Which Cossack leader plundered the Caspian's Persian shore in the 1660s before leading a great revolt against the tsar?

Stenka Razin. His river pirates spent a year and a half raiding the Persian coast, then turned on Moscow itself; he was captured and executed there in 1671.

Which city in Dagestan stands at the 'Caspian Gates', the narrow pass between the mountains and the sea?

Derbent. The town fills the strip of land between the heights and the shore, and Persian kings walled the gap shut, with iron gates and watchtowers, to keep raiders from the steppe off their frontier.

Astrakhan, the Tatar capital near the Caspian, was conquered for Russia in the 1550s by which tsar?

Ivan the Terrible. The conquest gave Moscow an outlet on the Caspian, and trade with Persia grew so quickly that English merchants were soon using the route as well.

Which Russian republic on the Caspian shore is home to Buddhists of Mongol descent?

Kalmykia. The Kalmyks are descended from Mongol nomads who moved west across the steppe in the 1600s and kept their Tibetan Buddhism in their new home by the Caspian.

How deep is the Caspian Sea at its deepest point?

About 1,000 metres. Yet the sea is wildly lopsided: one of its three basins is under five metres deep across most of its area and holds well under one percent of the water.

Which part of the Caspian Sea typically freezes over in winter?

The northern portion. It is not only the coldest end but the shallowest and freshest, mostly under five metres deep and fed by the big rivers, so it ices over from December to March.

Which forests on the Caspian's southern shore in Iran were added to UNESCO's World Heritage list in 2019?

Hyrcanian. The forests are living relics, 25 to 50 million years old, of the woods that once covered much of the northern temperate world, and the Caspian tiger once hunted in them.

Baku stands on which peninsula, a long spur of land thrusting out into the Caspian?

The Absheron. Its ground is so rich in oil that people were digging wells here for lamp fuel by the 15th century, four hundred years before the modern industry arrived.

As the oceans rise this century, what do climate models project for the Caspian's level?

A fall of many metres. A 2020 study projected a drop of 9 to 18 metres by 2100 as hotter air evaporates more water than the rivers bring in, enough to turn a quarter to a third of the sea into dry land.

Ships leaving the Caspian for the oceans cross a canal to the River Don, which flows into which sea?

The Sea of Azov. People had tried to cut that canal since the 1500s, but its 101 kilometres and 13 locks were not finished until 1952.

Which Central Asian president proposed a 'Eurasia Canal' west from the Caspian in 2007?

Nursultan Nazarbayev. He wanted to give landlocked Central Asia a way to the sea and priced the canal across southern Russia at six billion dollars, but as of 2025 it was still only a proposal.

The Caspian port of Krasnovodsk was renamed in 1993 after the grand title that which country's president gave himself?

Turkmenistan. Saparmurat Niyazov, president for life, styled himself Türkmenbaşy, 'Head of the Turkmen', and the port that took the title is still the country's ferry gateway across the Caspian.

Medieval Arab geographers, and Turks and Azeris to this day, name the Caspian after which vanished steppe empire?

The Khazars. Their khaganate ruled the steppe above the sea a thousand years ago, and long after it fell the sea stayed Hazar or Xəzər in the Turkic languages spoken around it.

The Caspian is an endorheic basin; what does that mean?

Its water has no outlet to the ocean. What the rivers bring in can leave only by evaporating, which is why the sea is salty and why its level rises and falls with the climate.

Which sea east of the Caspian, once the world's fourth-largest lake, has largely dried up since the 1960s?

The Aral Sea. Soviet planners diverted the two rivers that fed it to irrigate cotton fields, and within a few decades most of the lake had turned to desert.

Which Russian ruler led an army and a fleet down the Caspian in 1722 to seize Persia's western shore?

Peter the Great. His troops took the coast, but so many of them died of disease that it was a costly prize, and within thirteen years Russia had handed all of it back to Persia.

Which river supplies most of the fresh water flowing into the Caspian?

The Volga. Europe's longest river brings in roughly four-fifths of the inflow, so when dams and reservoirs upstream hold its water back, the level of the whole sea feels it.

Which raiders sailed down Russia's rivers to plunder the Caspian's shores in the 900s?

Vikings. Known in the east as the Rus, they struck the sea's ports several times, and in a great raid around 913 they plundered the whole southern shore, hit Baku and struck far beyond the coast.

The Baku-Tbilisi-Ceyhan pipeline carries Azeri oil to a port on which sea?

The Mediterranean. The route through Georgia and Turkey let Caspian oil flow there directly for the first time, and gave buyers in the West a supply that was neither Russian nor Middle Eastern.