Nakatsu is a city on Japan’s Kyushu Island. In the center, rebuilt Nakatsu Castle has an observation deck with coastal views. Nearby Goganji Temple is known for its striking red walls. In the mountains to the south, Aonodomon is an 18th-century tunnel carved out of the rock face. Rakan-ji Temple is decorated with thousands of stone Buddha statues. Trails lead to the rock formations and hot springs of Yabakei Gorge.