215
On June 20th, 2017 in the lowsec system of Seshala, the Northern Coalition alliance anchored a large Engineering Complex. The Imperium attacked before it could be brought online. Dreadnought and battleship fleets collided resulting in over 230 billion ISK worth of destruction.
The Engineering Complex was destroyed, but the Imperium lost 196 billion in the process.
The following cinematic newsreel of the event has been created for INN: