In a turn that surely no-one could have predicted, the Mongol leader dies, and the entire horde must travel thousands of miles back to their homeland to choose a new leader. The hill is unoccupied.
I arrive with a team of friendly wombats. They construct a system of tunnelled fortifications (the tunnels are all numbered, but for reasons they will not explain, the wombats omit Tunnel 17) and carefully scour the hill for any signs of magical space rifts, sentient statues, skin lizards and other such oddities.
My hill!