Camp Nou, Barcelona

Camp Nou, Europe's largest stadium at 99,354 capacity, is undergoing a €1.5 billion renovation, Espai Barça, to become a covered 105,000-seat arena with a translucent roof — 30% more enclosed than the average European stadium. The upgrade includes a 360-degree video board and improved acoustics, making it 40% louder than the typical rival for match-day atmosphere, cementing its place as a landmark of football innovation.