Horrible Histories goes pear-shaped in an explorers special, meeting Christopher Columbus as he tries to teach a class that the world is indeed, shaped like a pear. On the strict instructions of Emperor Nero, some hapless Roman centurions are quite literally stuck in the mud, searching for the source of the Nile. And intrepid Arctic explorer Peter Freuchen has to dig his way out of the snow with a frozen poo. From the Vikings' first small steps on American soil, to humankind's first giant leaps on the moon, join Horrible Histories on this epic adventure.