Geography

A tornado is precisely defined as a violently rotating column of air that extends from a thunderstorm (cumulonimbus cloud) to the ground. Hurricanes are large tropical cyclones forming over water, blizzards are severe snowstorms, and monsoons are seasonal wind shifts bringing significant rainfall.

Rift valleys are created at divergent boundaries where tectonic plates are moving away from each other (extending), causing the crust to thin and fracture. The central block of land then drops down relative to the blocks on either side, forming the valley.

Paris is the capital and largest city of France, located on the River Seine in the north-central part of the country. Rome is the capital of Italy, Madrid of Spain, and Berlin of Germany.

The Arid or Dry climate zone (often designated as B in the Köppen system) is uniquely defined not by temperature, but by the lack of precipitation relative to the demand for moisture (evapotranspiration). This moisture deficit is the characteristic that creates deserts (true arid) and steppes (semi-arid).

The Aurora (Aurora Borealis in the Northern Hemisphere and Aurora Australis in the Southern Hemisphere) is a natural light display in the Earth's sky, predominantly seen in high-latitude regions. It is caused by disturbances in the magnetosphere by the solar wind, leading to ionization and excitation of atmospheric constituents and the emission of light.

A fjord is a long, narrow inlet with steep sides or cliffs, created in a valley carved by glacial activity that has since been flooded by the sea.

Dry climates are defined by a moisture deficit; potential evapotranspiration (water lost to the atmosphere) must exceed the water gained via precipitation. This criterion holds true regardless of whether the climate is a hot desert or a cold desert.

While the Sun is far more massive, the Moon's much closer proximity to Earth means its gravitational pull has a greater differential effect on Earth's oceans, making it the primary cause of daily tides. The Sun also influences tides, especially during spring and neap tides, but the Moon's effect is dominant.

Polar climate zones are found at the highest latitudes, near the Earth's poles, and are defined by consistently frigid temperatures, often leading to perennial ice caps or glaciers, and brief, cool summer seasons.

Berlin is the unified capital city of Germany, having been restored to that role following the reunification of East and West Germany in 1990.