Metro lines can run underground, at ground level, or on elevated tracks. Stations connect residential neighborhoods, business districts, and transportation hubs across the city.

One of the first systematizers of geometric knowledge was the ancient Greek mathematician Euclid, who lived around the 3rd century BCE. His work Elements brought together the definitions, axioms, and theorems known at the time into a unified logical system. Euclidean geometry remained the foundation of mathematical education for many centuries. In the 17th century, René Descartes combined geometry with algebra, creating analytic geometry. By introducing coordinates, it became possible to describe geometric figures using equations. Later, the development of mathematical analysis, differential geometry, and the theory of spaces greatly expanded the field of geometric research.

The quick brown fox jumps over the lazy dog.