Built around the 12th Century, the ruins of Katsuren-jo (Katsuren Castle) sit atop a hill in Uruma, east of Okinawa City. It is an example of a gusuku, or traditional Okinawan castle. Because it lies on a peninsula bounded by the Pacific Ocean, it is also called the "Ocean Gusuku." Lord Amawari played an instrumental role in promoting trade and introducing overseas techniques and cultures to increase the prosperity of his domain. However, he was overthrown in 1458. Many fine pieces of tile and Chinese porcelain have been excavated from the structure, and it is now a World Heritage Site.
This little strip of land jutting out into the azure waters is one of the most picturesque sights in Onna. The area round Cape Maeda is a popular diving spot in the region and attracts adventure enthusiasts. For those who simply want to enjoy the scenery, the plateau-like features of the cape offer sweeping views and leisurely hikes. Don't miss the spectacular sunset from here.
At the Busena Marine Park on the southern outskirts of Nago City, tourists and locals alike can go underwater to explore the coral that thrives in the ocean, or board a glass-bottom boat to admire what lies beneath. The observatory looks like a tube perched off the coast of the island, and takes visitors down to the ocean floor for a panoramic view of Okinawa's marine life. Glass-bottom boats that go further out are on the beach.