Directly below where these two lines meet is the south pole. The Southern Hemisphere was mapped later than the Northern Sky. It was mapped because explorers needed information about the southern sky in order to navigate their ships at night. Astronomers worked out names for the Southern Constellations that weren't mythological. They named the constellations after the animals found in explorers' travels and the instruments they used to find their way amid the sea and stars.
Some constellations never rise in the north and can only be seen from the Southern Hemisphere.
In the Northern Hempisphere, stars turn in large circles around a star called Polaris. Polaris is also called the North Star because it constantly stays in the North, almost directly above Earth's North Pole. Many of the Northern constellations were mapped a very long time ago and named after the gods and heroes of ancient Greek mythology.