$12256 / $11500
High quality, photographic, 6-sided, 2048x2048 sized skyboxes made by Emil Persson, aka Humus, taken from http://www.humus.name
This pack contains 7 skyboxes with rocky setting. Some have water and/or people there and all have some structures in the background.
These were previously under a custom license, but he re-licensed them to CC-BY-3.0.