I made this environment over the course of 2 years, working on it bit by bit in my spare time.
It originally started in Unreal Development Kit (UDK), but I then had decided to produce it inside of CryENGINE 3, because of it's real-time based workflow (Over UDK's baked lightmap procedures).
Software used: Maya, ZBrush, Mudbox, 3D-Coat, Topogun, & Photoshop.
All 3D assets created by me from scratch. The things not created by me are the trees, small frogs, and various small flora.