What are the best exploration based games on PS4?

Skyrim inherits the stories and world-building of The Elder Scrolls series, which stretches back 20 years. It has numerous stories surrounding the various races (orcs, elves, lizardmen, demons, etc.), mythical beasts, gods, cataclysmic events, parallel worlds, and just about any fantasy trope you could think off. What's even better you can read the lore in books found in-game, allowing you to immerse yourself for countless hours.