Update: I noticed that there’s a confusion will this World be included in the Base Game or not. SimGuruMarion confirmed that this world WILL be included in The Sims 4 Base Game! (Source)
GamesRadar confirmed that The Sims 4’s 2nd world is named Oasis Springs! Take a look at what do they have to say about it:
The Sims 4 will have another environment to compliment the lush Willow Creek neighborhood, and this one’s more on the parched side. The recently unveiled Oasis Springs district is set in the middle of an arid desert, and has the look of suburban Las Vegas. This locale is filled with desert-themed charm, complete with set-pieces like cactuses and shed-sized air conditioners (and is that a Western-motif diner I see in the background?). You can still build lovely homesteads with plenty of modern comforts. You’ll likely have tons of fun in this…wellspring? Fountain? Watering hole? It’s right on the tip of my tongue…
Love the waterfall, is that a footbridge going across in front of it??