Towards the end of the nineteenth century, some Russians launched the first land submarine, designed to travel on land. It's mission was to reach the site of the black pole, and claim it as their own. The submarine worked by moving so quickly in the water, that it built up enough momentum to travel through the ground as soon as it reached the shore. It attempted this, and travelled a few hundred miles through the land, but unfortunately for the Russians, it had not enough momentum to complete the journey, and came to a halt a few feet from the black pole, and immediately rose to the surface. Because of this enormous pressure change, the crew of three died instantly, and turned into oil, which to this very day flows in and out of the iron submarine, with rotten sandwiches floating in it.
An attempt was made by another submarine two years later, but they made the mistake of using a kaleidoscope instead of a periscope, and so as soon as they encountered a ship they immediately surrendered, thinking they were surrounded.