Early explorers risked their lives to explore uncharted places because getting things from over seas like spices, silk, porcelain, gems, and precious metals could make them great profits.
it might to be hard determine the exact cause of an event because it may have occurred long time ago and no one thought to report it or no one was around it during the occurrence
Countries would want to keep or make nuclear or bio weapons to become world powers or have the upper hand against other nations without that kind of power
