The Blue Mountains National Park is located in New South Wales, approximately 80 km (50 miles) west of Sydney. Its proximity to the biggest city in Australia has made this scenic park a popular day trip for both tourists and locals alike. The park is probably best known for the Three Sisters, a rock formation that towers 900 meter (3000 foot) above the Jamison Valley. The Blue Mountains National Park features miles of trails for hikers and mountain bikers, and it is also a popular natural playground for adventurers who enjoy adrenaline sports such as rock climbing and abseiling. Visitors who prefer a more tame way to enjoy the Blue Mountains National Park can climb aboard the glass-roofed carriages of the Katoomba Scenic Railway, which is the steepest passenger railway in the world.