As one of the numerous caves in Sequoia National Park, Crystal Cave is a landscape of mineralogical beauty, decorated with stalagmites and stalactites all around. It is only accessible through guided tours, and after passing its spider-web gate, visitors will get to marvel at the longest cave in California. While it may seem as if it is just an ordinary old cave, there is a vast array of tours available for visitors. One of them is bound to suit your fancy. Families can embark on the standard 50-minute tour to learn more about the cave, while adventure seekers can take on the Adventure Tour, which is about five hours long and requires visitors to be physically fit. Equipment is provided for the tours, but do expect to get dirty! As the cave is a constant 9 degrees Celsius regardless of the weather, do make sure to keep yourself warm as you explore this beautiful cave.