This video explains the properties of parallel lines and transversals in geometry. The instructor, Robert Ahdoot, uses an analogy in which he compares lines and transversals to the streets of Manhattan, New York. Continuing with this comparison, he goes over corresponding angles of two parallel lines cut by the same transversal, also explaining when they're equal. He then shows where interior and exterior angles may be found, and then goes over whether two angels are same-side or alternate, depending on their position relative to the transversal. This video gives a summary of parallel lines and transversals in geometry, providing a good starting point for understanding more complicated geometric concepts.