In 2026, Heathrow Terminal 5 (T5) remains one of the most impressive aviation structures in the world. The main terminal building, known as T5A, is massive, covering an area of 353,020 square meters. To put that in perspective, the entire T5 complex, which includes the main building and two satellite buildings (T5B and T5C), sits on a 260-hectare site—roughly the same size as London’s Hyde Park. The main building alone is nearly a quarter of a mile long. It was designed to handle an annual capacity of 30 million passengers and is the primary hub for British Airways. The facility includes 62 aircraft stands, a 4,000-space multi-story car park, and its own dedicated rail station for the Heathrow Express and Elizabeth Line. Its sheer scale once made it the largest construction site in Europe during its multi-year development.