Standing in the middle of the bridge, looking at the caves across (where people go back and forth), turn left and cross the rest of the bridge. From there, take the stairs up. At the top of the stairs, take the right and continue along that path, which will take you to the bifurcation you’ve passed while coming down from Stop 8 to Stop 9. There, take the left. That narrow path will take you back to the wide path that connects it to the Unfinished Well, with it standing practically in front of you. Go to that path and, keeping the Unfinished Well to your right, go forward. Stay on that path until the very end, where you will find the entrance to a cave. To explore the Aquarium, you need to go into this cave, but beware: it is extremely dark inside and you will need some aid. If your phone has a flashlight, turn it on to navigate its space. Go inside, take the spiral staircase down, and continue through the cave. Once inside, you’ll find a structure with water: stop there facing it to learn about Regaleira’s Aquarium.