Here are some in game screenshots the "Mad Mage Cave" created with the TES Construction Kit

Screenshots

Here are a few screenshots for a level I created for Intruder

Screenshots

Here are a number of screenshots from levels created using Unreal Tournament 2004. The goal of these two maps was to accurately model real world locations: Warkworth castle in England and the Temple of Hatsheput in Egypt. The emphasis was more on accurately modeling geometry rather than creating spaces that are conducive to gameplay.

Screenshots

Renders from models created in Maya.

Renders