First, this is just incredible. Second, how in the world did we figure it out?
A honeybee will waggle her abdomen in a specific way to communicate the location of a nectar source. The actual description starts around 1:49:
The duration of her waggle indicates the distance to the nectar source. The longer the waggle, the further the flower. And the angle at which she dances across the cone tells them the direction to the flower in relation to the sun. Her instructions are remarkably accurate and can pinpoint the location of a nectar source over 6 kilometers (3.7 miles) away.