Excellent post on the importance of sleep. Did you know that we used to sleep in two cycles and for much more time then we now do until very recently?

Also from that article:

Now we have so much artificial light that after a 1994 earthquake knocked out power, some concerned residents of Los Angeles called the police to report a "giant, silvery cloud" in the sky above them. It was the Milky Way. They had never seen it before.

I wonder what else we lose living in a "modern" society.