1) The Cuban Missile Crisis in 1962 brought the United States and the Soviet Union to the brink of nuclear war during the Cold War.

2) The discovery of the Americas by Christopher Columbus in 1492 opened up new trade routes and had a profound impact on world history.

3) 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.

4) The blue whale is the largest animal to have ever existed, with an average length of about 82 feet (25 meters).