The official Canadian delegation to NATO helpfully tweeted out this map for the benefit of the Russian government, which recently explained that Russian troops were only appearing to invade eastern Ukraine because they had crossed the border "by accident."
It's not just Twitter snark: Russia does genuinely seem to doubt that Ukraine is a distinct country. Russian President Vladimir Putin has spoken at great length about "protecting" the ethnic Russian Ukrainians and Russian-speaking Ukrainians from non-existent fascist threats. Russia's rising far-right movement has long seen the southern part of Ukraine as Novorossiya, or "New Russia," and rightfully theirs. All of which helps to explain why Moscow thinks it is okay for Russian troops to invade Ukraine, as they have been doing all summer.
But there is one way in which the joke here is on NATO. The Ukrainian region of Crimea, that little peninsula jutting into the Black Sea, is marked on this map as part of Ukraine. Legally speaking, that is true, and since the Soviet Union collapsed it has been part of Ukraine. But it is now de facto part of Russia, which invaded and annexed the territory in March. While Western countries and Ukraine are insisting that Crimea is part of Ukraine, the facts on the ground are pretty clear that Crimea is part of Russia now, whether we like it or not.