World Lakes and Seas Quiz: Identify Major Lakes, Seas & Coastal Features

A sea is typically a large saline water body often connected to an ocean, while a lake is an inland basin filled with freshwater or saline water and usually surrounded by land. However, some large saline lakes like the Caspian Sea are historically called seas despite being landlocked.

The Caspian Sea is the world's largest enclosed inland water body and is often classified as the largest lake by surface area. It is saline and landlocked, so some classifications call it an inland sea; definitions vary between geological, hydrological, and geopolitical contexts.

The Aral Sea shrank primarily because rivers feeding it (the Amu Darya and Syr Darya) were extensively diverted for irrigation and cotton production during the Soviet era. Partial recovery is possible with improved water management and regional cooperation, but full restoration is unlikely without major changes to water use.

Lake Baikal in Siberia holds the largest volume of freshwater in the world, containing about 20% of the planet's unfrozen surface freshwater. Its depth and large basin make it uniquely voluminous.

The Great Lakes of North America (Superior, Michigan, Huron, Erie, and Ontario) are freshwater lakes and together they form the largest group of freshwater lakes by total area on Earth.

The Dead Sea has an extremely high salinity—several times that of ocean water—due to high evaporation and limited outflow. This creates an environment too saline for most aquatic life, so only specialized microorganisms and some halophilic organisms can survive there, and fish cannot.