BT Tower

2015 marked 50 years since the official opening of the iconic BT Tower in central London. The tower, which was previously known as the Post Office Tower, was commissioned by the General Post Office (GPO) to support the British Telecom microwave network that was used to carry telecommunications traffic from the capital to the rest of the country.

The tower is 189 metres high to the top of the aerial and cost £2.5 million to build – the equivalent of £45.3 million in today's money. It can sway as much as 20 centimetres in the wind so it is no wonder that the foundations are the same depth as a stack of 12 double-decker buses - 53 metres deep.