Okunoin Cemetery is a sacred Buddhist site and cemetery located on Mount Kōya in Japan. Established in 835, it houses the mausoleum of Kūkai, the founder of the Shingon school of esoteric Buddhism. With over 200,000 graves and memorial monuments, it's considered the largest cemetery in Japan. Visitors can stroll along a 2-kilometer-long walkway lined with towering conifers, leading to Kūkai's mausoleum. The site is known for its serene atmosphere and the belief that Kūkai is in eternal meditation, making it a popular pilgrimage destination for Buddhists.