The morning twilight, as seen from our house, is one of the most beautiful things I've ever seen. If you catch it from the beginning, the sky is an inky blue-black, and the moon is still up. There's a deep crimson glow on the horizon, and as you stand quietly and watch, it swells to form a beautiful red/crimson/purple/inky blue transition.
Then the sun rises and it's gone until the next day.
I almost never get to see it, unless I happen to have been up all night.