The South Pointing Chariot is a wonder of engineering from ancient China. Legend suggests it was invented by the Yellow Emperor arround 2600 BC (though it probably wasn’t!).
The south pointing chariot has an arm which always points south. THis isn’t a compass. This is done entirely through gears, getting the radio and track right. No matter how the chariot twists and turns, provided the wheels are on the ground, the arm will point south.
As New Scientist seem to want to point out – you can build one from Lego.
There you go. A little bit blurred in the time-speed sections but worth the wait.