Awa Sand Pillars

The Awa Sand Pillars, known in Japanese as Awa no dochū, are a formation of sandstone and gravel hoodoos in the city of Awa, Tokushima Prefecture, on the island of Shikoku, Japan, within Dochū Kotsu Prefectural Natural Park. The pillars formed from ancient layers of gravel and sand deposited by the nearby Yoshino River and later compressed into sandstone, then shaped by differential erosion as the compacted gravel wore away more slowly than the surrounding sandstone, a process believed to have taken around 1.2 million years. The pillars range from about 10 meters for the smaller formations up to 90 meters for the tallest, named Wadakuto, and the site is one of only three such hoodoo formations known worldwide, alongside examples in the Rocky Mountains and in Tyrol. It was designated a National Natural Monument of Japan in May 1935, with the earliest recorded mention of the site dating to the year 800.