Trama
Take a deep dive with this documentary investigating the hidden secrets of one of our oldest, and most crucial, networks - the sewers. A tour of the latest solution - London's Tideway Tunnel - reveals its staggering scale - a 16-mile-long storage tank to hide sewage beneath the river Thames. There is also a trip to Hadrian's Wall to marvel at how the Romans handled the sewage issue almost 2,000 years ago.