The Line is a heavily publicized linear urban development planned within the NEOM region of northwestern Saudi Arabia, designed as a zero-carbon smart city spanning 170 kilometers. Envisioned to house millions of residents without conventional roads, cars, or carbon emissions, the vertical city relies entirely on renewable energy sources and high-speed subterranean transit. Due to extreme engineering complexities, physical constraints, and escalating financial budgets, portions of the project have been scaled back or re-evaluated.