The Atal Tunnel, an engineering marvel, is the world's longest high-altitude tunnel, boasting a series of challenging features including variable geology, tectonic thrust, heavy snowfall, high overburden, limited shaft options, expansive cross-sectional area, powerful ventilation systems, high stresses, fluctuating temperatures, rock spalling, heat tracing units, and electrical systems suited for high altitudes. Despite nearly a decade of construction, this remarkable 9 km tunnel overcame obstacles such as avalanches, severe snowfall, and challenging geographic conditions to claim the title of the world's longest highway tunnel above 10,000 feet. This single-tube, two-lane tunnel features a horseshoe-shaped design and connects the southern Himalayan valley of Manali with the northern Lahaul Valley in India.