The Earth at night. Looking at the U.S., we can easily see many of the major cities and the Interstate system. Lots and lots of lights.
When we look at East Asia, we see that Japan, China, and South Korea are well-lit. North Korea has a few lights in Pyongyang - nothing anywhere else.
Say what you will about India, it's very well-lit. The lights stop at the Himalaya.
In North Africa, the Nile River shows up very well in Egypt surrounded by the mostly unlit Sahara Desert.
In Australia, the East Coast, Perth, and a few dots in the Outback. Good place to do astronomy - lots of dark areas.
What on Earth are those bright lights east of Madagascar?
Google Earth shows them as Mauritius and Reunion.
I'd love to see a very high resolution image of the Earth at night. I'm sure a lot of interesting things could be seen.