Sakai was developed as the port town. In the middle ages, it was considered as Asian Venice. During the Sengoku period, the entire city was surround by moat, and rule by the union of Sakai merchants. The entire town was once destroyed in the siege of Osaka, and reconstructed after that in 1615.
Today, it is modern city with many historical sites including great Kofun.
Emperor Nintoku Kofun (仁徳天皇陵) is one of Kofun, the Emperor's Mausoleum, located in Sakai, Osaka. It is front square back circle Kofun with moats and its size is 2,718m of perimeter, 656m east-to-west, 793m north-to-south, and 35m high. It is the biggest mausoleum in the world. Because of its huge size, it is also called Daisen Ryo. The official name is "Mozunomimiharanonakanomisasagi." People in Sakai call this Kofun, "Goryo" with full of respect. You cannot enter inside of Kofun, but there is worship place on the top of Kofun.
Sakai Yamaguchi House (堺山口家住宅) is one of the remaining Sakai merchant house in Sakai, Osaka. The building was constructed in 1615 right after the siege of Osaka. It is registered as national important cultural asset. It represents the life of Sakai merchant during Edo period.
Seigakuin (清学院) is an old Fudo temple located in Sakai, Osaka. In Edo period, it was used for Terakoya, the elementary school. The building was constructed in late Edo period. The temple was for Shugendo, the religion of the sacred mountains. It displays those historical records and items.
Sakai Gov. Office Observatory (堺市役所展望ロビー) is one of the popular tourist spot in Sakai, Osaka. It is on 21st floor that is 80m high and has great panorama view of Sakai. This is the only public place that you can see Kofun from high angle. There is a cafe on the observatory.
Myokokuji Temple (妙國寺) is one of Nichiren Buddhism Temple located in Osaka. It was established in 1562 by Priest Nichikou. Its garden is the only Japanese Karesansui Style Garden with Cycad. There is a grave of 11 Tosa Samurai who did seppuku in 1868.