Unprecedented footage shows front line of Ukrainian conflict with Russia

As tensions with Russia continue to rise in eastern Europe, CNN gains unprecedented access to the Ukrainian president on the front line in Donbas, eastern Ukraine. Ukrainian military officials tell CNN they estimate more than 50,000 Russian troops are massing near the border. CNN’s Matthew Chance reports.As tensions with Russia continue to rise in eastern Europe, CNN gains unprecedented access to the Ukrainian president on the front line in Donbas, eastern Ukraine. Ukrainian military officials tell CNN they estimate more than 50,000 Russian troops are massing near the border. CNN’s Matthew Chance reports.