Ukrainian soldiers stand in front of huge Soviet-era arch in Kiev on December 2, 2018, symbolizing Ukraine and Russia's friendship and union, where an unknown artist added a crack following recent tensions. - Tensions between Ukraine and Russia rose on November 25, when Russian forces seized three Ukranian navy vessels and their crew. Ukraine imposed martial law for 30 days in 10 regions that border Russia, the Black Sea and the Azov Sea on November 28. (Photo by Sergei SUPINSKY / AFP)