How do you build an unbuildable tower?

After 144 years the tallest tower on the Sagrada Familia is finally complete, but when Gaudi first designed it, the technology to build the tower didn’t exist. We’re joined by Tristram Carfrae, structural engineer and designer at Arup who was tasked with this impossible feat over a decade ago. With the reappearance of screwworm in North America, we ask – is it ever acceptable to intentionally drive a species to extinction? Tom is joined by Dr Gregory Kaebnick from the Hastings Center for Bioethics to dive into the science that could make it happen and the ethics stopping us. Four in five of us will check the weather daily, but do we really know what our apps are telling us? Meteorologist Simon King guides us through the complex models behind these forecasts that govern our daily decisions. Plus, science journalist Caroline Steel is in the studio bringing us the scientific discoveries the headlines missed, but that you need to know. Presenter: Tom Whipple Producer: Kate White Editor: Martin Smith Production Co-ordinator: Jana Bennett-Holesworth