Russia's prized bridge to Crimea has become a top target for Ukraine, and the damage is bad news for Moscow's grip on the peninsula.

• The $3.6 billion bridge Russia built to link its mainland to Crimea has been hit and is no longer usable for crossing.
• The bridge was central to Russia's plan for holding and supplying Crimea, so knocking it out is a real blow.
• Russia once showed it off as a symbol of strength; now it stands as a symbol of how exposed that supply line is.
• Cutting the crossing squeezes how Russia moves troops and gear into the peninsula.

Outlook: Expect Russia to scramble to repair or defend the route while Ukraine keeps hunting the bridge as a prime target.