On the livescience.com website, I read something pretty amazing: “If you were standing atop a mountain surveying a larger-than-usual patch of the planet, you could perceive bright lights hundreds of miles distant. On a dark night, you could even see a candle flame flickering up to 30 miles (48 km) away.” No telescopes or night-vision goggles needed—the human eye is so profoundly designed that even long distances can be spanned with clear sight.