One of my favorite contests every year (though I have yet to enter myself) is the Classic-Castle Mini-Castle Contest, full of teeny tiny medieval towns and, well, lots of castles, of course. ;)
The “Living Tree” by Tânia Baixinhos reminds me of something from a Miyazaki movie or a Final Fantasy game:
Check out the Brickshelf gallery for details like the lake, fields, villagers, and all the little houses in the branches of the tree.