To stop it from falling over, the building has vast footings.
Above ground, the structure has a plan of 60m by 40m, but below ground its raft measures 100m 2. The tower sits in one corner of that raft.
Not only is the raft huge in area. It is between 5m and 7m deep, and founded on 1.2m1.5m diameter bored concrete piles up to 56m long.
'There's no rock. The ground is sand, gravel, clay, ' says McGowan. 'The raft redistributes the overturning moment from the tower into the piles, while its mass ensures that even under seismic load, the piles don't go into tension.'