Arctic Circle

The Arctic Circle is a land of snow and ice surrounding the northern pole of the planet Earth. Perpetually frozen, it is hostile to many life forms, including humans and giant robots, which tend to end up frozen there.

Movie continuity
Questing after the All Spark, Megatron approached Earth, but hit a "radiation blind spot" in the planet's upper atmosphere, and lost track of the cube. He made his landing near the planet's north pole. Unfortunately, he landed on relatively thin ice, which quickly gave way under his weight and the heat from his atmospheric entry. The freezing water quickly sent his systems into shock and shut him down.

Centuries later, Megatron's frozen form was discovered by the National Arctic Circle Expedition, lead by Captain Archibald Witwicky in 1897.

By 1899, the predecessors of Sector 7 had erected an environment dome over Megatron's landing site, to excavate, secure and study him. Megatron would remain in the location until 1935, when he was moved to Hoover Dam.