1) The most-watched TV series finale in the United States was "MAS*H," with an estimated 105 million viewers.

2) The Great Barrier Reef in Australia is the largest coral reef system in the world and is visible from space.

3) The first commercially available digital camera, the Dycam Model 1, was introduced in 1990 and had a resolution of 376 x 240 pixels.

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