Temporary Decepticon base

The Giant Decepticon Symbol is a Decepticon operations center in the cartoon portion of the Generation 1 continuity family.

"Excellent! No one will ever find us here!"
"Uh -- are you sure about --"
"I said, NO ONE WILL EVER FIND US HERE."

Ever the masters of stealth and subtlety, the Decepticons created a temporary operations base in the desert, shaped like a Giant Decepticon Symbol.

The base was accessible through the "chinks" in the stylized insignia's "face". It came complete with computers and monitoring systems that allowed the Decepticons to watch events in the outside world, as well as energy cages for holding captured Autobots, though only Starscream got to actually test them out.

The Decepticons used it to rewire toasters. Enter the Nightbird

From Teletraan I: The Transformers Wiki, a Wikia wiki.