When civilization collapses, it'll be at the hands of 200+ wanton Supermen. They will terraform Earth into one giant desert to facilitate the absorption of the Sun's yellow rays. Then they will pose for photo ops and laugh, laugh, laugh.
But for real, these photos were taken on September 4 at Burning Man 2010. Attendees apparently broke the world record for the most people dressed a Superman in one place. The previous record was 122, but this group mustered up 200 or so Mad Max-like Kryptonians. Allison at Mod Mischief (who took the top and middle photos) has tips on how to put together a Superman outfit on the cheap.
This reminds me somewhat of 1995's Superman: At Earth's End, in which an unshaven Superman from a post-apocalyptic Earth killed Hitler's cloned twins with a giant gatling gun.