#sea level

• Altitude — The vertical height of a point, a landform, or an object (such as an aircraft) measured relative to a determined reference level, which most frequently is the mean sea level (absolute altitude) or the earth's surface immediately below (relative altitude).
• Baku — The capital and largest city of Azerbaijan, located on the southern coast of the Absheron Peninsula, on the shores of the Caspian Sea. This major structural hub is situated 28 meters below sea level, making it the lowest national capital in the world and the largest city located below sea level; it is globally renowned as a historical energy hub for oil extraction and for its old town (Icherisheher), listed as a UNESCO World Heritage site.