Britain Beneath Your Feet BBC1, 8pm
According to Dallas Campbell we can only truly understand the familiar world around us by discovering the hidden wonders beneath our feet. In this two-part documentary, computer graphics are used to strip away the earth and lay bare this secret world of hidden rivers, mines, power stations, iconic buildings and amazing wildlife. Campbell finds out how the Shard of London - the tallest skyscraper in Western Europe - stays standing on soft clay.