1. Cost £4.3 billion – largest single building project in Europe by value.

2. Terminal 5 has the capacity to serve around 30 million passengers a year; taking the number of people Heathrow will serve to around 90 million each year.

3. The square footage of Terminal 5’s three buildings adds up to more than all of Heathrow’s existing terminal buildings put together.

4. The main Terminal 5 building has a footprint equivalent to 60 football pitches, measuring 396m by 176m. At 22m, its basement is deep enough to swallow an eight storey building, and is believed to be the largest ever excavated in the UK.

5. The terminal building is almost 400m (a quarter of a mile) long – that's the distance from Bond St to Oxford Circus in London or the equivalent of 40 double-decker buses parked end to end.

6. The new 87m high control tower is double the height of the old Heathrow tower and the tallest in the UK.

7. London clay was predicted to swell by up to 250mm over the coming 50 years. To accommodate this, the buildings’ base slabs have been formed above the ground, propped on piles, leaving voids beneath into which the ground is allowed to expand.

8. The main terminal building, Terminal 5A, has 1,100 piles.

9. Pile testing enabled the number of piles with enlarged bases to be cut by 90% – from 450 to 45 on the main building – saving time and reducing the volume of concrete needed by 30%.

10. Total volume of earthworks equals 6.5 million m3 – enough to fill the new Wembley Stadium one and a half times.

11. Giant staples were used to hold the Heathrow Express tunnels in place while excavation of the basement for Terminal 5C was carried out.

12. There are five new tunnels serving Terminal 5 with a combined length of 14km.

13. The 1.2km, twin bore airside road tunnel is, at 8.8m diameter, the largest of the five new Terminal 5 tunnels. It crosses the existing Piccadilly Line tunnel with 3m clearance and the Heathrow Express tunnel with 5m clearance, and also passes beneath taxiways.

14. Vertical and horizontal alignment of the airside road tunnel was tuned to minimise ground movement resulting from tunnelling.

15. German TBM supplier Herrenknecht designed a bespoke earth pressure balance machine for the job.

16. The observational method was used to achieve materials and time savings during basement excavation and construction of tunnel portals.

17. Up to 6,000 staff were working on Terminal 5 at the project peak (both on-and off-site). However, over the life of the project around 60,000 will be involved with building T5.

18. It took an estimated 37 million manhours (people working on and off site) to build Terminal 5.

19. There are 1 million square metres of new apron and taxiway pavement for T5.

20. Use of recycled concrete and reduction of the pavement slab thickness through the use of high strength concrete eliminated 27,000 truck movements.