1) The Great Lakes, consisting of Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario, form the largest group of freshwater lakes on Earth by total area. They are shared by the United States and Canada and are of significant ecological and economic importance.

2) The world's first paper money was created in China over 1,000 years ago.

3) The human brain has a storage capacity equivalent to around 2.5 petabytes, which is roughly equivalent to three million hours of TV shows.

4) The Earth's core is primarily composed of iron and nickel and is as hot as the surface of the sun.