The Black Sea has a deadly naval mine problem that will long outlast the Ukraine war

• The Black Sea faces a long-term danger from naval mines in the Russia-Ukraine war.
• Ships have struck drifting mines in the last two years as Ukraine struggled to clear shipping routes.
• But even after the war, it's not clear how long it'll take to clear the waters.

Against all odds, Ukraine has gained the initiative in the Black Sea.

But a silent threat under the waves is poised to long outlast Russia's aggression: an unknown number of naval mines likely laid by both sides.

Even their locations — classified information to each of the warring parties — have become an open question as multiple incidents indicate that some have been drifting.