"Columbus´ Egg is a turn of phrase that describes a stupefying simple solution for what might appear to be a complex unsolvable problem.
Anecdotal - folklore suggests that when Christopher Columbus returned from his voyage of discovery of the Americas in the year 1493 he was having dinner with Cardinal Mendoza who commented that it had not really been such a big deal to discover the Americas - in fact anyone could have done it. In retaliation Christopher Columbus challenged all persons present to stand an egg on end. Everyone tried but failed.
Christopher then took the egg - he tapped it gently on the table breaking it slightly and, with this, the egg stood on its end.
Hence the Egg of Columbus.
Allegedly the other persons did protest that they too could have done this but Christopher simply responded that yes they could have done it but he actually did it.