once you have tasted the taste of sky, you will forever look up - Leonardo da Vinci

For once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return.

Men do wrong to lament the flight of time, complaining that it passes too quickly and failing to perceive that its period is sufficiently long; but a good memory, with which nature has endowed us, causes everything that is long past to appear to us to be present.

Those men who are inventors and interpreters between Nature and Man, as compared with boasters and declaimers of the works of others, must be regarded and not otherwise esteemed than as the object in front of a mirror, when compared with its image seen in the mirror. For the first is something in itself, and the other nothingness. — Folks little indebted to Nature, since it is only by chance that they wear the human form and without it I might class them with the herds of beasts.