So I was moseying around on the lots in my sims' neighborhood and came across a closed off mine. It said I needed level 10 Handiness to unblock it. So many sim days later, I got level 10 and instantly went over to where I found it. It's at the Desert Bloom park location in Oasis Springs. Somewhere along the boundaries of the location. After unblocking it, it gives you the option to Explore it. While exploring it chance cards pop up and if you answer incorrectly, you leave and start over. If you answer the 4 cards correctly, it will ask you if you want to Enter the Forgotten Grotto. After a load screen I walked into this: Isn't it beautiful?! I actually thought that my sim was going to be gone forever and my home lot was loading lol! After a minute, plants will start sprouting and you will find mounds that you can dig into. I found some pretty uncommon things there but the plants were all pretty generic. I don't know if it all will change if I go again. There are also 3 fishing spots that I didn't get a chance to really fish in (I didn't have bait because I wasn't expecting this lol!) Also I thought that the light rays which kind of focus on the other end of the location would be some alien craft that was going to whisk me away, but that did not happen. Near the entrance, there is a bunch of old looking things that includes a poorly made wooden toilet. Other than that and the collectibles and fishing spots there wasn't much to do. I am wondering if there is another secret location for Willow Creek because when I was trying to go through the chance cards, my sim left feeling Embarrassed because he got lost exploring a "Secret Neighborhood Location" (something along the lines of that). After I rested up from this adventure, I went to the park in Willow Springs and did not find an abandoned mine, but maybe I should be looking for something else. Either way I wanted to share this because it's a beautiful setting that I'm sure some story makers out there would like to utilize this in the future! Happy simming!