In 1950, repairs were made to the stone base of the former donjon, which had been in ruins since the Great Kantō earthquake, and the area was made into the Odawara Castle Park, which included an art museum, local history museum, city library, amusement park and zoo. The three-tiered, five-storied donjon, the top floor of which is an observatory, was rebuilt in 1960 out of reinforced concrete to celebrate the 20th anniversary of the proclamation of Odawara as a city. However, the reconstructed donjon is not historically accurate, as the observation deck was added at the insistence of the Odawara City tourism authorities. Plans have been discussed since the late 1960s on a more accurate restoration of the central castle grounds to its late Edo period format. These plans resulted in the reconstruction of the in 1971, the in 1997, and the in 2009. The castle tower was remodelled from July 2015 until April 2016 to improve earthquake resistance and to modernise its exhibits. Odawara City government donated all entry fees on the day of the re-opening to Kumamoto City government, to be put towards repairs to Kumamoto Castle that was damaged in the 2016 Kumamoto earthquakes.