Wolf 359
From FEInfobase
Wolf 359 is a red dwarf star located 8 light years from Earth. It was the site of the Battle of Wolf 359, one of the most brutal defeats in Federation history up to that time. In 2366, a single Borg Cube engaged and defeated an armada of 40 Federation starships that had been hastily assembled to defend Earth. 39 were destroyed outright, and the last (the USS Endeavour) was severely damaged. The death toll was nearly 11,000, though it will never be known for certian which of these were assimilated instead of being killed.
The battle lasted approximately twenty four minutes from first shot to last.