FOSS gamedev and creative worlds

for some reason i cannot find my 'worlds' folder anywhere. I installed it through terminal and it works fine.
any body able to help me?
also i'm using fedora 18, i think

Have you installed it globally, or in a run_in_place folder?
If its global, the worlds are in ~/.minetest/ (a hidden folder in your home directory).
If you installed a run_in_place version, the worlds are simply in the worlds/ folder in the minetest folder.