Long ago, there lived an ancient race called the Druids. Nobody knew who they were, or what they were doing.

The Dragon Mound is a dome-shaped structure surrounded by stone columns similar in appearance to Stonehenge. The structure was built in ancient Britain as a time traveling device by the wizard Beorht, and was so named after a wandering, fire-breathing dragon took up residence inside.

The interior of the mound appears man-made, illuminated by a glowing green orb.

Fiction

The Transformers cartoon

In an emergency search for energy, Starscream fiddled with the stone tablet that apparently controlled the time-traveling properties of the Dragon Mound and inadvertently sent himself, Rumble, Ramjet and Ravage back to the year 543 AD.

Warpath collapsed the entrance while firing on the Decepticons, then he and Hoist worked at clearing the rubble in order to follow Starscream and the others inside. Oh, and Spike came along too.

At the conclusion of their misadventures in the 6th century, Warpath used Beorht's Dragon's Bane to defeat the dragon and then the Transformers and Spike entered the mound to return to their own time. A Decepticon Raider in King Arthur's Court

Games

The Transformers (PS2)

Optimus Prime was reminded of Dragon Mound when a trio of Autobots claimed to be from the future to prevent a disaster from occurring. Knowing time travel was possible, he chose to believe their story. The Transformers