The Doctor: You can't rule the world in hiding. You've got to come out on the balcony sometimes and wave a tentacle, if you pardon the expression.
The Control Voice: It is said that if you move a single pebble on the beach, you set up a different pattern, and everything in the world is changed. It can also be said that love can change the future, if it is deep enough, true enough, and selfless enough. It can prevent a war, prohibit a plague, keep the whole world... whole.
Uncle Martin: We don't have love at first sight on Mars. Either it was too silly to bother with, or it was something we discarded in our Dusk Ages.
Tim O'Hara: You mean the Dark Ages?
Uncle Martin: We were never that primitive.