This lovely public park was once the grounds of a feudal lord's residence in the late seventeenth century, and it was restored in 1927 after being destroyed in the Great Kanto Earthquake. The pond at the center of the park was originally fed by the Sumida River, with the water level rising and falling with the tides. Nowadays water pumps are used to simulate the effect of the tides.
The Japanese Sword Museum is located in one corner of the park, and the third-floor terrace of the museum provides a nice overall view of the park. There are also a number of other museums and attractions in the Ryogoku area.