The main donjon of the Edo Castle was completed in 1607. It standed 58 meters high above the ground with five storied building with a gold stylized shachihoko (an imaginary sea animal and looks like dolphin) on top, it was the largest donjon ever built in Japan, but it was destroyed in the Great Fire of 1657. Since then it has never been reconstructed and only the stone wall that formed its foundation remains today. The present stone walls are about 10 meters high. Because the landscaping work for the opening of the East Gardens was carried out in 1968, and this area was piled up by the earth.