Daniel Brown/Business Insider
Ukrainian soldiers stationed near the village of Luhanske were in their bunker on the night of July 31st when an 82mm mortar shell landed directly on top, according to the Kyiv Post.
Their fortification did its job: No one was injured.
The war in eastern Ukraine started shortly after Russia annexed Crimea in 2014 when pro-Russian separatists proclaimed parts of the Donbas as independent states known as the Donetsk People's Republic and Luhansk People's Republic.
Russia has funded, managed and supplied weapons to these rebel states ever since. Moscow admitted it was helping the rebels in late 2015 after repeated denials to the contrary.
Since the 2015 Minsk II peace agreement, in which Kiev and Russian-backed separatists agreed to withdraw their tanks and heavy artillery from the 250 mile long front lines, the war has largely turned into stagnant trench warfare.
Reminiscent of World War I, the two sides these days mostly lob mortars and grenades and trade sniper fire at and with each other. In response, soldiers on both sides dig networks of trenches and deep bunkers for protection.
And the bunkers have only gotten more complex and elabarote over the last three years.
Here's what they look like.