Picture this ground long before any lawn was planted. Before the Azuchi-Momoyama period, the whole area of Hibiya Park was sea. It was a body of water called the Hibiya Inlet, and the land you are walking on was reclaimed from it over time. Then came the age of Edo Castle. The park lies just outside the castle's Hibiya Gate, which made this prime real estate. From the Edo period right up to the end of the shogunate, the land held the upper residences of powerful domains, among them the Matsudaira Hizen-no-kami. After the Meiji era began, the ground changed purpose again and became an army parade ground. So before it was a garden, this was a place of sea, then of feudal lords, then of drilling soldiers. That neighborhood still shapes the park. The name Chiyoda, the ward you are in, means field of a thousand generations. It was inherited from Chiyoda Castle, another name for Edo Castle, whose site is now the Imperial Palace just to the north.