Estimated to be between 3,000 and 7,000 years old, Jomon-sugi is an enormous yakusugi cedar that predates the pyramids — and though no longer living, its gnarled, moss-covered trunk remains a staggering sight. Reaching it requires a 19.5-kilometre, eight-to-ten-hour round trip from the Arakawa trailhead, through ancient forest so primordial it inspired the world of Princess Mononoke. The hike demands serious stamina but rewards with an encounter that genuinely rearranges your sense of time. From March through November, you must take a mandatory mountain bus from the Yakusugi Museum parking lot.