Ukraine's counteroffensive is now into its fourth month. Kyiv's forces, bolstered by Western tanks and weapons, are putting pressure on Russian positions but have yet to achieve a major breakthrough. But all across Ukraine, there is a sense that things could change very quickly. A section of defences could collapse, and fortunes could turn. Sky News spoke to military expert Sean Bell about the different parts of the frontline and how each could be a flashpoint, from crossing the Dnipro in the west to the push to liberate Bakhmut in the east. We've zeroed in on five locations and ask,...