Drones have taken over the battlefield in Russia’s war on Ukraine. Now the deadliest war since World War 2 - the conflict is being fought in a way unlike we’ve ever seen before. Tens of thousands of drones are being produced every day - and Ukrainian military drone operator Serhii Andriev says keeping up with technological advancements is extremely difficult. Hear the full story on The world, the universe and us, a news podcast for the insatiably curious, hosted by Rowan Hooper and Penny Sarchet