as fighting intensifies in some of ukraine's biggest cities, those watching and waiting across the country for the war to come to them are preparing. our eastern europe correspondent sarah rainsford is in the south eastern city of dnipro and has been speaking to people readying for battle. air raid siren blares. it is the most chilling sound. but this wail is a call to safety. a warning to head underground. it's very cold, very basic, but its cover in a war that's escalating fast and seems to have no rules. the bunker was built under a factory under the soviet union. it was supposed to be used in event of nuclear attack, and now it's being used in modern—day ukraine when sirens wail again.