BT remains one of the largest owners of telecommunications towers in the UK and were a major node in its microwave network. Its BT Tower in London is notable for numerous reasons such as being the tallest building in the UK from its construction in the 1960s until the early 1980s, its revolving restaurant at the top known as 'Top of the Tower' in operation through the late 1960s and 1970s, and remains one of the UK's most important communications nerve centres, the heart of a vast broadcasting and communications network. It carries approximately 95% of the UK's TV content, including live broadcasts and 99% of all live football games as well as pioneering the first international HD, 3D and 4K television transmissions. It serves media production and distribution customers around the world and as part of the Things Connected Network launched in London, it became the highest building in the world to host an Internet of things (IoT) base station in September 2016. Some of its towers are: