Triangle shaped 4 lights on bottom, made no sound, and moved really fast.

Craft hoverd overhead for at least 20 min.  It made no sound.  Triangle shaped with 4 lights on the bottom, one at each triangle point.  One light in the middle. 
This thing was huge, at least as big as a footballfield.  I'm not really sure how long we watched it.  But when it took off it whent straight up, until it was only a speck in the sky and shot off at a right angle. 
It was the biggest thing I've, ever seen.  When it was overhead it completley blocked out the sky.
Witness indicates that the date of the sighting is approximate.  PD