What are the best PC games with detailed worlds that reward exploration?

The Elder Scrolls III: Morrowind is an open world fantasy action role-playing video game developed by Bethesda Game Studios. For the same price [Oblivion](https://store.steampowered.com/app/22330/The_Elder_Scrolls_IV_Oblivion_Game_of_the_Year_Edition/) is an even better deal, rated 94 on [MetaCritic](https://www.metacritic.com/game/pc/the-elder-scrolls-iv-oblivion?ftag=MCD-06-10aaa1f) but this might not run smooth on older low spec systems. Also interesting (and free) is [The Elder Scrolls II: Daggerfall](https://www.slant.co/topics/12748/viewpoints/7/~open-world-old-rpgs-ever~the-elder-scrolls-ii-daggerfall).