In the seven days since this conflict began, southern Ukraine has become a critical defensive front against Russia's advances.
Moscow has chosen to lay siege to multiple cities there, viewing the region as strategically vital to the success of the invasion as a whole.
Not only would controlling the coast sever the rest of Ukraine from the sea, it would also create a direct connection between Russian-annexed Crimea and the Russian-speaking Donbas region.
Let's take a minute to recap what's been happening there:
Kherson has a population of 280,000 and is so far the largest city to fall to Russian forces. It sits on the banks of the Dnieper River, giving those in control access to critical canals supplying water to Crimea.
Another large port is Mariupol, population 430,000, which is being shelled and encircled. If successfully seized, Russia will have established a direct link between eastern Ukraine and Crimea, both of which are already Russian-controlled.
Crimea is a Russian-speaking part of Ukraine that was annexed by Moscow in 2014. It's where Russia launched much of this southern offensive from one week ago.
Odesa is Ukraine's third-largest city and the country's most important port on the Black Sea, as well as being a major oil terminus. So far its one million residents have escaped the worst of the fighting. This is because Russia has currently made no concerted effort to advance west of Kherson - beyond isolated reports of paratrooper landings.
