Grutas Tolantongo, nestled in the mountains of Hidalgo, Mexico, is a hidden gem known for its warm thermal waters and stunning natural beauty. While this location isn't in Mexico City itself, it's widely considered a must-do day trip for visitors to the capital and can be easily booked on Viator for a hassle-free tour. The park, managed by local families, offers visitors a chance to relax and rejuvenate in its hot springs, pools, caves, and lush green valley. With Instagram-worthy spots like suspension bridges and turquoise rivers, Grutas Tolantongo is a must-visit destination for those seeking a unique outdoor experience with therapeutic benefits.